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| 1. | Akram, Sahar Javaid; Meißner, Sophie; Kümmel, Stephan: Analyzing Electronic Excitations and Exciton Binding Energies in Y6 Films. In: Advanced Functional Materials, n/a (n/a), pp. 2419236, 2025, ISSN: 1616-3028 . (Type: Journal Article | Abstract | Links | BibTeX) @article{https://doi.org/10.1002/adfm.202419236, title = {Analyzing Electronic Excitations and Exciton Binding Energies in Y6 Films}, author = {Sahar Javaid Akram and Sophie Meißner and Stephan Kümmel}, url = {https://advanced.onlinelibrary.wiley.com/doi/abs/10.1002/adfm.202419236}, doi = {https://doi.org/10.1002/adfm.202419236}, issn = {1616-3028 }, year = {2025}, date = {2025-02-21}, journal = {Advanced Functional Materials}, volume = {n/a}, number = {n/a}, pages = {2419236}, abstract = {Abstract The Y6 molecule is one of the most promising non-fullerene acceptors. Based on first-principles calculations, this paper analyzes how the separation of an electronic excitation into electron and hole densities is influenced by the interaction between different Y6 molecules. By calculating the optical and the fundamental gaps of ensembles of Y6 molecules that realistically represent a film, their corresponding exciton binding energies are obtained. The combination of range separation, optimal tuning, and dielectric screening endows the presented density functional theory calculations with predictive power. The calculations reveal that the electronic excitations, characterized as electron–hole pairs via their natural transition orbitals, spread across multiple Y6 molecules. A distinct decrease in the exciton binding energy is correlated to a notable charge separation, and the exciton binding energy saturates in ensembles of six to seven Y6 molecules at ≈0.25 electronvolt (eV). These findings contribute to explaining the efficient charge separation in films of Y6. They also give a guideline for the number of molecules that theoretical models should take into account when they aim at a realistic description of charge separation.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Abstract The Y6 molecule is one of the most promising non-fullerene acceptors. Based on first-principles calculations, this paper analyzes how the separation of an electronic excitation into electron and hole densities is influenced by the interaction between different Y6 molecules. By calculating the optical and the fundamental gaps of ensembles of Y6 molecules that realistically represent a film, their corresponding exciton binding energies are obtained. The combination of range separation, optimal tuning, and dielectric screening endows the presented density functional theory calculations with predictive power. The calculations reveal that the electronic excitations, characterized as electron–hole pairs via their natural transition orbitals, spread across multiple Y6 molecules. A distinct decrease in the exciton binding energy is correlated to a notable charge separation, and the exciton binding energy saturates in ensembles of six to seven Y6 molecules at ≈0.25 electronvolt (eV). These findings contribute to explaining the efficient charge separation in films of Y6. They also give a guideline for the number of molecules that theoretical models should take into account when they aim at a realistic description of charge separation. |
| 2. | Kuhn, Meike; Wenzel, Felix A; Greve, Christopher; Kreger, Klaus; Schwartzkopf, Matthias; Schmidt, Hans-Werner; Grüninger, Helen; Herzig, Eva M: Tailored Supramolecular Additives to Control the Crystallization Process and Morphology of MAPbI3. In: Small, 21 (9), pp. 2410230, 2025, ISSN: 1613-6810. (Type: Journal Article | Abstract | Links | BibTeX) @article{Kuhn2025, title = {Tailored Supramolecular Additives to Control the Crystallization Process and Morphology of MAPbI3}, author = {Meike Kuhn and Felix A Wenzel and Christopher Greve and Klaus Kreger and Matthias Schwartzkopf and Hans-Werner Schmidt and Helen Grüninger and Eva M Herzig}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/smll.202410230}, doi = {https://doi.org/10.1002/smll.202410230}, issn = {1613-6810}, year = {2025}, date = {2025-02-05}, journal = {Small}, volume = {21}, number = {9}, pages = {2410230}, abstract = {Abstract Perovskite films feature unique optoelectronic properties, rendering them promising for electronic devices. The properties depend on the morphology on a broad range of length scales from nanometers to millimeters, influenced by a variety of factors. However, controlling the morphology is challenging. A tailored supramolecular additive, N, N’-bis(2-aminoethyl) terephthalamide is developed to control the intermediate and perovskite crystallization of methyl ammonium lead iodide (MAPbI3) and enhance the thermal and moisture stability in the final film. Reversible coordinative interactions of the carbonyl groups with Pb2+ ions via Lewis acid-base adduct and subsequent ion–ion interactions of the peripheral ammonium groups with the perovskite grain boundaries are combined which is stabilized by a strong hydrogen bonding pattern formed between the amide moieties of the additive molecules. Adding low amounts of this additive to the precursor solution significantly decelerates the structure formation and systematically reduces the crystallite size. Slower growth of the intermediate phases and the incorporation of the additive to the grain boundary is observed with multiple time-resolved techniques. Evidence for the formation of single-molecule interlayers between the MAPbI3 crystals and the presence of directed supramolecular interaction between additive molecules is shown. Transferability of this approach to other perovskites is anticipated, paving the way to improved processing control and stability.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Abstract Perovskite films feature unique optoelectronic properties, rendering them promising for electronic devices. The properties depend on the morphology on a broad range of length scales from nanometers to millimeters, influenced by a variety of factors. However, controlling the morphology is challenging. A tailored supramolecular additive, N, N’-bis(2-aminoethyl) terephthalamide is developed to control the intermediate and perovskite crystallization of methyl ammonium lead iodide (MAPbI3) and enhance the thermal and moisture stability in the final film. Reversible coordinative interactions of the carbonyl groups with Pb2+ ions via Lewis acid-base adduct and subsequent ion–ion interactions of the peripheral ammonium groups with the perovskite grain boundaries are combined which is stabilized by a strong hydrogen bonding pattern formed between the amide moieties of the additive molecules. Adding low amounts of this additive to the precursor solution significantly decelerates the structure formation and systematically reduces the crystallite size. Slower growth of the intermediate phases and the incorporation of the additive to the grain boundary is observed with multiple time-resolved techniques. Evidence for the formation of single-molecule interlayers between the MAPbI3 crystals and the presence of directed supramolecular interaction between additive molecules is shown. Transferability of this approach to other perovskites is anticipated, paving the way to improved processing control and stability. |
| 3. | Kutter, Maximilian; Hilgert, Annika; Maier, Maximilian; Schilling, Monja; Greve, Christopher R; Loukrakpam, Rameshwori; Hagemeier, Wiebke; Rosin, Andreas; Muggli, Mark; Herzig, Eva M; Zeis, Roswitha; Böhm, Thomas; Gerdes, Thorsten; Roth, Christina: LiF@PFSA-Based Composite Membranes for PEM Fuel Cells at Intermediate Temperature Conditions. In: ACS Applied Polymer Materials, 7 (2), pp. 599–610, 2025. (Type: Journal Article | Abstract | Links | BibTeX) @article{Kutter2025, title = {LiF@PFSA-Based Composite Membranes for PEM Fuel Cells at Intermediate Temperature Conditions}, author = {Maximilian Kutter and Annika Hilgert and Maximilian Maier and Monja Schilling and Christopher R Greve and Rameshwori Loukrakpam and Wiebke Hagemeier and Andreas Rosin and Mark Muggli and Eva M Herzig and Roswitha Zeis and Thomas Böhm and Thorsten Gerdes and Christina Roth}, url = {https://doi.org/10.1021/acsapm.4c02540}, doi = {10.1021/acsapm.4c02540}, year = {2025}, date = {2025-01-05}, journal = {ACS Applied Polymer Materials}, volume = {7}, number = {2}, pages = {599–610}, abstract = {Polymer electrolyte membrane fuel cells (PEMFCs) operating at temperatures above 100 °C offer an interesting opportunity for heavy-duty applications. Especially for intermediate operating temperatures between 110 and 130 °C (IT-PEMFC), faster reaction kinetics, higher tolerance to fuel impurities, and water flooding as well as improved heat management of the fuel cell system have been observed. Perfluorosulfonic acid-based membranes (PFSAs) can be modified by incorporating additives or (nano)particle filler systems to improve their thermal and mechanical stability, proton conductivity, and long-term performance at these increased temperatures. Here, we investigate the effect of lithium fluoride particles embedded in PFSA membranes on their water retention behavior as well as on membrane durability in single-cell tests at elevated PEMFC operating temperatures of up to 120 °C. The lithium fluoride nanoparticle-modified membrane shows increased cell performance under both standard and intermediate temperature conditions. The observed performance boost can be explained by an increased mechanical stability at elevated temperatures of the membrane, due to stabilizing hydrophobic and hydrophilic domains, and an increased water uptake and storage capability, especially at low humidity levels during full cell operation. We propose that the nanoparticles adsorb water molecules by hydrogen bond formation, thus enhancing proton conductivity even at high temperatures resulting in these increased full cell performances of the LiF@PFSA-based composite membrane.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Polymer electrolyte membrane fuel cells (PEMFCs) operating at temperatures above 100 °C offer an interesting opportunity for heavy-duty applications. Especially for intermediate operating temperatures between 110 and 130 °C (IT-PEMFC), faster reaction kinetics, higher tolerance to fuel impurities, and water flooding as well as improved heat management of the fuel cell system have been observed. Perfluorosulfonic acid-based membranes (PFSAs) can be modified by incorporating additives or (nano)particle filler systems to improve their thermal and mechanical stability, proton conductivity, and long-term performance at these increased temperatures. Here, we investigate the effect of lithium fluoride particles embedded in PFSA membranes on their water retention behavior as well as on membrane durability in single-cell tests at elevated PEMFC operating temperatures of up to 120 °C. The lithium fluoride nanoparticle-modified membrane shows increased cell performance under both standard and intermediate temperature conditions. The observed performance boost can be explained by an increased mechanical stability at elevated temperatures of the membrane, due to stabilizing hydrophobic and hydrophilic domains, and an increased water uptake and storage capability, especially at low humidity levels during full cell operation. We propose that the nanoparticles adsorb water molecules by hydrogen bond formation, thus enhancing proton conductivity even at high temperatures resulting in these increased full cell performances of the LiF@PFSA-based composite membrane. |
| 4. | Giri, Amal Kanta; Oberhofer, Harald: Large scale atomistic and quantum mechanical study of Na+ ion transport in liquid electrolytes for batteries. In: Journal of Molecular Liquids, 413 , pp. 125920, 2024, ISSN: 0167-7322. (Type: Journal Article | Abstract | Links | BibTeX) @article{Giri2024b, title = {Large scale atomistic and quantum mechanical study of Na+ ion transport in liquid electrolytes for batteries}, author = {Amal Kanta Giri and Harald Oberhofer}, url = {https://www.sciencedirect.com/science/article/pii/S0167732224019792}, doi = {https://doi.org/10.1016/j.molliq.2024.125920}, issn = {0167-7322}, year = {2024}, date = {2024-11-01}, journal = {Journal of Molecular Liquids}, volume = {413}, pages = {125920}, abstract = {Lithium–ion batteries (LIBs) have long dominated energy storage markets due to their high energy density and reliability. However, concerns over lithium scarcity and geographic distribution necessitate alternatives. Sodium-ion batteries (SIBs) offer a promising solution due to sodium's abundance, cost-effectiveness, and favorable electrochemical properties. This study investigates Na+ ion transport, aggregation, and performance in various organic electrolytes using molecular dynamics (MD) simulations and density functional theory (DFT) calculations. The electrolytes studied include ethylene carbonate (EC), propylene carbonate (PC), dimethoxyethane (DME), and dimethyl carbonate (DMC) at 320 K. We focused on conductivity, diffusivity, and survival probability of Na+ ions at different salt concentrations. Furthermore, the solvation structure and the binding energy of ions in the electrolytes are thoroughly analyzed. Key findings reveal that at 2 M salt concentration, Na+ ion diffusivity and ionic conductivity follow the order EC>PC>DME>DMC. Increasing salt concentration decreases self–diffusion coefficients of Na+ and PF6− ions across all electrolytes, affecting conductivity. EC shows the highest ionic conductivity at both 1 M and 2 M salt concentrations. These insights suggest that a 2 M NaPF6 concentration in EC optimizes ionic conductivity, making it ideal for high–performance SIBs. This study provides crucial understanding for optimizing electrolytes in SIBs, advancing their development for scalable energy storage solutions.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Lithium–ion batteries (LIBs) have long dominated energy storage markets due to their high energy density and reliability. However, concerns over lithium scarcity and geographic distribution necessitate alternatives. Sodium-ion batteries (SIBs) offer a promising solution due to sodium's abundance, cost-effectiveness, and favorable electrochemical properties. This study investigates Na+ ion transport, aggregation, and performance in various organic electrolytes using molecular dynamics (MD) simulations and density functional theory (DFT) calculations. The electrolytes studied include ethylene carbonate (EC), propylene carbonate (PC), dimethoxyethane (DME), and dimethyl carbonate (DMC) at 320 K. We focused on conductivity, diffusivity, and survival probability of Na+ ions at different salt concentrations. Furthermore, the solvation structure and the binding energy of ions in the electrolytes are thoroughly analyzed. Key findings reveal that at 2 M salt concentration, Na+ ion diffusivity and ionic conductivity follow the order EC>PC>DME>DMC. Increasing salt concentration decreases self–diffusion coefficients of Na+ and PF6− ions across all electrolytes, affecting conductivity. EC shows the highest ionic conductivity at both 1 M and 2 M salt concentrations. These insights suggest that a 2 M NaPF6 concentration in EC optimizes ionic conductivity, making it ideal for high–performance SIBs. This study provides crucial understanding for optimizing electrolytes in SIBs, advancing their development for scalable energy storage solutions. |
| 5. | Wenzel, Felix A; Stäter, Sebastian; O’Reilly, Padraic; Kreger, Klaus; Köhler, Jürgen; Hildner, Richard; Schmidt, Hans-Werner: Isolated Hierarchical Superstructures with Highly Oriented P3HT Nanofibers. In: Macromolecules, 57 , pp. 10389 – 10398, 2024, ISSN: 1520-5835 . (Type: Journal Article | Abstract | Links | BibTeX) @article{Wenzel2024, title = {Isolated Hierarchical Superstructures with Highly Oriented P3HT Nanofibers}, author = {Felix A Wenzel and Sebastian Stäter and Padraic O’Reilly and Klaus Kreger and Jürgen Köhler and Richard Hildner and Hans-Werner Schmidt}, url = {https://doi.org/10.1021/acs.macromol.4c01618}, doi = {10.1021/acs.macromol.4c01618}, issn = {1520-5835 }, year = {2024}, date = {2024-10-30}, journal = {Macromolecules}, volume = {57}, pages = {10389 – 10398}, abstract = {The preparation of supramolecular mesoscale structures with high intrinsic order and orientation based on π-conjugated systems is of fundamental interest for studying their photophysical characteristics as well as for potential applications in (nano)photonics. However, the preparation, isolation and transfer of individual structures to substrates without compromising their structural integrity is challenging. Here we report on the controlled formation of hierarchical superstructures based on poly(3-hexylthiophene) (P3HT) comprising highly ordered and oriented P3HT nanofibers with lengths of up to 20 μm via a two-step self-assembly process. In the first step, we prepare defined supramolecular ribbons of N,N′-1,4-phenylenebis[4-pyridinecarboxamide]. In the second step, these ribbons act as efficient nucleation sites for the transcrystallization of P3HT into μm-long nanofibers from solution. The resulting shish-kebab-like superstructures can be purified and deposited on substrates without compromising their structural integrity. The densely packed and well-arranged P3HT nanofibers within the isolated superstructures feature a high orientational order parameter close to one up to a distance of 15 μm away from the initial nucleation sites. A systematic variation of photoluminescence spectra along the P3HT nanofibers in isolated superstructures indicates an increasing defect density toward the nanofiber end due to fractionation during growth. We anticipate that these findings can be transferred to designing and realizing superstructures as components for nanophotonic devices or light-harvesting antennae. year = 2024}, keywords = {}, pubstate = {published}, tppubtype = {article} } The preparation of supramolecular mesoscale structures with high intrinsic order and orientation based on π-conjugated systems is of fundamental interest for studying their photophysical characteristics as well as for potential applications in (nano)photonics. However, the preparation, isolation and transfer of individual structures to substrates without compromising their structural integrity is challenging. Here we report on the controlled formation of hierarchical superstructures based on poly(3-hexylthiophene) (P3HT) comprising highly ordered and oriented P3HT nanofibers with lengths of up to 20 μm via a two-step self-assembly process. In the first step, we prepare defined supramolecular ribbons of N,N′-1,4-phenylenebis[4-pyridinecarboxamide]. In the second step, these ribbons act as efficient nucleation sites for the transcrystallization of P3HT into μm-long nanofibers from solution. The resulting shish-kebab-like superstructures can be purified and deposited on substrates without compromising their structural integrity. The densely packed and well-arranged P3HT nanofibers within the isolated superstructures feature a high orientational order parameter close to one up to a distance of 15 μm away from the initial nucleation sites. A systematic variation of photoluminescence spectra along the P3HT nanofibers in isolated superstructures indicates an increasing defect density toward the nanofiber end due to fractionation during growth. We anticipate that these findings can be transferred to designing and realizing superstructures as components for nanophotonic devices or light-harvesting antennae. year = 2024 |
| 6. | Lebeda, Timo; Aschebrock, Thilo; Kümmel, Stephan: Balancing the Contributions to the Gradient Expansion: Accurate Binding and Band Gaps with a Nonempirical Meta-GGA. In: Phys. Rev. Lett., 133 , pp. 136402, 2024, ISSN: 1079-7114. (Type: Journal Article | Links | BibTeX) @article{Lebeda2024, title = {Balancing the Contributions to the Gradient Expansion: Accurate Binding and Band Gaps with a Nonempirical Meta-GGA}, author = {Timo Lebeda and Thilo Aschebrock and Stephan Kümmel}, url = {https://link.aps.org/doi/10.1103/PhysRevLett.133.136402}, doi = {10.1103/PhysRevLett.133.136402}, issn = {1079-7114}, year = {2024}, date = {2024-09-01}, journal = {Phys. Rev. Lett.}, volume = {133}, pages = {136402}, publisher = {American Physical Society}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
| 7. | Yao, Yuxuan; Oberhofer, Harald: Designing building blocks of covalent organic frameworks through on-the-fly batch-based Bayesian optimization. In: The Journal of Chemical Physics, 16 , pp. 074102 , 2024, ISSN: 0021-9606. (Type: Journal Article | Abstract | Links | BibTeX) @article{Yao2024b, title = {Designing building blocks of covalent organic frameworks through on-the-fly batch-based Bayesian optimization}, author = {Yuxuan Yao and Harald Oberhofer}, url = {https://doi.org/10.1063/5.0223540}, doi = {10.1063/5.0223540}, issn = {0021-9606}, year = {2024}, date = {2024-08-21}, journal = {The Journal of Chemical Physics}, volume = {16}, pages = {074102 }, abstract = {In this work, we use a Bayesian optimization (BO) algorithm to sample the space of covalent organic framework (COF) components aimed at the design of COFs with a high hole conductivity. COFs are crystalline, often porous coordination polymers, where organic molecular units—called building blocks (BBs)—are connected by covalent bonds. Even though we limit ourselves here to a space of three-fold symmetric BBs forming two-dimensional COF sheets, their design space is still much too large to be sampled by traditional means through evaluating the properties of each element in this space from first principles. In order to ensure valid BBs, we use a molecular generation algorithm that, by construction, leads to rigid three-fold symmetric molecules. The BO approach then trains two distinct surrogate models for two conductivity properties, level alignment vs a reference electrode and reorganization free energy, which are combined in a fitness function as the objective that evaluates BBs’ conductivities. These continuously improving surrogates allow the prediction of a material’s properties at a low computational cost. It thus allows us to select promising candidates which, together with candidates that are very different from the molecules already sampled, form the updated training sets of the surrogate models. In the course of 20 such training steps, we find a number of promising candidates, some being only variations on already known motifs and others being completely novel. Finally, we subject the six best such candidates to a computational reverse synthesis analysis to gauge their real-world synthesizability.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this work, we use a Bayesian optimization (BO) algorithm to sample the space of covalent organic framework (COF) components aimed at the design of COFs with a high hole conductivity. COFs are crystalline, often porous coordination polymers, where organic molecular units—called building blocks (BBs)—are connected by covalent bonds. Even though we limit ourselves here to a space of three-fold symmetric BBs forming two-dimensional COF sheets, their design space is still much too large to be sampled by traditional means through evaluating the properties of each element in this space from first principles. In order to ensure valid BBs, we use a molecular generation algorithm that, by construction, leads to rigid three-fold symmetric molecules. The BO approach then trains two distinct surrogate models for two conductivity properties, level alignment vs a reference electrode and reorganization free energy, which are combined in a fitness function as the objective that evaluates BBs’ conductivities. These continuously improving surrogates allow the prediction of a material’s properties at a low computational cost. It thus allows us to select promising candidates which, together with candidates that are very different from the molecules already sampled, form the updated training sets of the surrogate models. In the course of 20 such training steps, we find a number of promising candidates, some being only variations on already known motifs and others being completely novel. Finally, we subject the six best such candidates to a computational reverse synthesis analysis to gauge their real-world synthesizability. |
| 8. | Zhang, Heyou; Dharpure, Pankaj; Philipp, Michael; Mulvaney, Paul; Thelakkat, Mukundan; Köhler, Jürgen: Purely Optical, Reversible, Read-Write-Erase Cycling Using Photoswitchable Beads in Micropatterned Arrays. In: Advanced Optical Materials, 12 (26), pp. 2401029, 2024, ISSN: 2195-1071. (Type: Journal Article | Abstract | Links | BibTeX) @article{Zhang2024d, title = {Purely Optical, Reversible, Read-Write-Erase Cycling Using Photoswitchable Beads in Micropatterned Arrays}, author = {Heyou Zhang and Pankaj Dharpure and Michael Philipp and Paul Mulvaney and Mukundan Thelakkat and Jürgen Köhler}, url = {https://advanced.onlinelibrary.wiley.com/doi/abs/10.1002/adom.202401029}, doi = {https://doi.org/10.1002/adom.202401029}, issn = {2195-1071}, year = {2024}, date = {2024-07-16}, journal = {Advanced Optical Materials}, volume = {12}, number = {26}, pages = {2401029}, abstract = {Abstract Using surface-templated electrophoretic deposition, arrays of polymer beads (photonic units) incorporating photo-switchable DAE molecules are created, which can be reversibly and individually switched between high and low emission states by direct photo-excitation, without any energy or electron transfer processes within the molecular system. The micropatterned array of these photonic units is spectroscopically characterized in detail and optimized with respect to both signal contrast and cross-talk. The optimum optical parameters including laser intensity, wavelength and duration of irradiation are elucidated and ideal conditions for creating reversible on/off cycles in a micropatterned array are determined. 500 such cycles are demonstrated with no obvious on/off contrast attenuation. The ability to process binary information is demonstrated by selectively writing information to the given photonic unit, reading the resultant emissive signal pattern and finally erasing the information again, which in turn demonstrates the possibility of continuous recording. This basic study paves the way for building complex circuits using spatially well-arranged photonic units.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Abstract Using surface-templated electrophoretic deposition, arrays of polymer beads (photonic units) incorporating photo-switchable DAE molecules are created, which can be reversibly and individually switched between high and low emission states by direct photo-excitation, without any energy or electron transfer processes within the molecular system. The micropatterned array of these photonic units is spectroscopically characterized in detail and optimized with respect to both signal contrast and cross-talk. The optimum optical parameters including laser intensity, wavelength and duration of irradiation are elucidated and ideal conditions for creating reversible on/off cycles in a micropatterned array are determined. 500 such cycles are demonstrated with no obvious on/off contrast attenuation. The ability to process binary information is demonstrated by selectively writing information to the given photonic unit, reading the resultant emissive signal pattern and finally erasing the information again, which in turn demonstrates the possibility of continuous recording. This basic study paves the way for building complex circuits using spatially well-arranged photonic units. |
| 9. | Schröder, Dennis; Kreger, Klaus; Mansfeld, Ulrich; Schmidt, Hans-Werner: Controlled Surface Decoration with Functional Supramolecular Nanofibers by Physical Vapor Deposition. In: Advanced Materials Interfaces, 11 (25), pp. 2400259, 2024, ISSN: 2196-7350. (Type: Journal Article | Abstract | Links | BibTeX) @article{Schröder2024, title = {Controlled Surface Decoration with Functional Supramolecular Nanofibers by Physical Vapor Deposition}, author = {Dennis Schröder and Klaus Kreger and Ulrich Mansfeld and Hans-Werner Schmidt}, url = {https://advanced.onlinelibrary.wiley.com/doi/abs/10.1002/admi.202400259}, doi = {https://doi.org/10.1002/admi.202400259}, issn = {2196-7350}, year = {2024}, date = {2024-06-27}, journal = {Advanced Materials Interfaces}, volume = {11}, number = {25}, pages = {2400259}, abstract = {Abstract Surface decoration of support structures by physical vapor deposition (PVD) of small molecular building blocks offers a versatile platform to realize functional supramolecular nanofibers in a controlled manner and with tailored properties. Here, details on the preparation of surface-decorated polyamide fabrics by PVD using N1,N3,N5-tris[2-(diisopropylamino)-ethyl]-1,3,5-benzenetricarboxamide (1) as a molecular building block are reported. It is shown that a defined morphology with uniform nanofiber length can be achieved, which is controlled by the PVD conditions. The functional periphery of supramolecular nanofibers of 1 allows the immobilization of gold nanoparticles (AuNPs). This results in AuNP-loaded nanostructures with a high surface area, which can be used as a heterogenous catalyst for the reduction of 4-nitrophenol in aqueous media. The surface-decorated support structures with firmly deposited AuNPs also provide the opportunity to conveniently reuse these structures without compromising the catalytic performance. This approach provides fabrication strategies for the controlled surface decoration of macroscopic support structures with small molecular building blocks by PVD with the potential to realize functional robust supramolecular nanofibers for various catalytic or filtration applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Abstract Surface decoration of support structures by physical vapor deposition (PVD) of small molecular building blocks offers a versatile platform to realize functional supramolecular nanofibers in a controlled manner and with tailored properties. Here, details on the preparation of surface-decorated polyamide fabrics by PVD using N1,N3,N5-tris[2-(diisopropylamino)-ethyl]-1,3,5-benzenetricarboxamide (1) as a molecular building block are reported. It is shown that a defined morphology with uniform nanofiber length can be achieved, which is controlled by the PVD conditions. The functional periphery of supramolecular nanofibers of 1 allows the immobilization of gold nanoparticles (AuNPs). This results in AuNP-loaded nanostructures with a high surface area, which can be used as a heterogenous catalyst for the reduction of 4-nitrophenol in aqueous media. The surface-decorated support structures with firmly deposited AuNPs also provide the opportunity to conveniently reuse these structures without compromising the catalytic performance. This approach provides fabrication strategies for the controlled surface decoration of macroscopic support structures with small molecular building blocks by PVD with the potential to realize functional robust supramolecular nanofibers for various catalytic or filtration applications. |
| 10. | Brütting, Moritz; Bahmann, Hilke; Kümmel, Stephan: Predicting fundamental gaps accurately from density functional theory with non-empirical local range separation. In: The Journal of Chemical Physics, 160 (18), pp. 181101, 2024, ISSN: 0021-9606. (Type: Journal Article | Abstract | Links | BibTeX) @article{Brütting2024, title = {Predicting fundamental gaps accurately from density functional theory with non-empirical local range separation}, author = {Moritz Brütting and Hilke Bahmann and Stephan Kümmel}, url = {https://doi.org/10.1063/5.0204379}, doi = {10.1063/5.0204379}, issn = {0021-9606}, year = {2024}, date = {2024-05-14}, journal = {The Journal of Chemical Physics}, volume = {160}, number = {18}, pages = {181101}, abstract = {We present an exchange–correlation approximation in which the Coulomb interaction is split into long- and short-range components and the range separation is determined by a non-empirical density functional. The functional respects important constraints, such as the homogeneous and slowly varying density limits, leads to the correct long-range potential, and eliminates one-electron self-interaction. Our approach is designed for spectroscopic purposes and closely approximates the piecewise linearity of the energy as a function of the particle number. The functional’s accuracy for predicting the fundamental gap in generalized Kohn–Sham theory is demonstrated for a large number of systems, including organic semiconductors with a notoriously difficult electronic structure.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We present an exchange–correlation approximation in which the Coulomb interaction is split into long- and short-range components and the range separation is determined by a non-empirical density functional. The functional respects important constraints, such as the homogeneous and slowly varying density limits, leads to the correct long-range potential, and eliminates one-electron self-interaction. Our approach is designed for spectroscopic purposes and closely approximates the piecewise linearity of the energy as a function of the particle number. The functional’s accuracy for predicting the fundamental gap in generalized Kohn–Sham theory is demonstrated for a large number of systems, including organic semiconductors with a notoriously difficult electronic structure. |
| 11. | Carta, Alberto; Wittmann, Bernd; Kreger, Klaus; Schmidt, Hans-Werner; Jansen, Thomas L C; Hildner, Richard: Spatial Correlations Drive Long-Range Transport and Trapping of Excitons in Single H-Aggregates: Experiment and Theory. In: The Journal of Physical Chemistry Letters, 15 (10), pp. 2697-2707, 2024, ISSN: 1948-7185, (PMID: 38427597). (Type: Journal Article | Abstract | Links | BibTeX) @article{Carta2024, title = {Spatial Correlations Drive Long-Range Transport and Trapping of Excitons in Single H-Aggregates: Experiment and Theory}, author = {Alberto Carta and Bernd Wittmann and Klaus Kreger and Hans-Werner Schmidt and Thomas L C Jansen and Richard Hildner}, url = {https://doi.org/10.1021/acs.jpclett.3c03586}, doi = {10.1021/acs.jpclett.3c03586}, issn = {1948-7185}, year = {2024}, date = {2024-03-01}, journal = {The Journal of Physical Chemistry Letters}, volume = {15}, number = {10}, pages = {2697-2707}, abstract = {Describing long-range energy transport is a crucial step, both toward deepening our knowledge on natural light-harvesting systems and toward developing novel photoactive materials. Here, we combine experiment and theory to resolve and reproduce energy transport on pico- to nanosecond time scales in single H-type supramolecular nanofibers based on carbonyl-bridged triarylamines (CBT). Each nanofiber shows energy transport dynamics over long distances up to ∼1 μm, despite exciton trapping at specific positions along the nanofibers. Using a minimal Frenkel exciton model including disorder, we demonstrate that spatial correlations in the normally distributed site energies are crucial to reproduce the experimental data. In particular, we can observe the long-range and subdiffusive nature of the exciton dynamics as well as the trapping behavior of excitons in specific locations of the nanofiber. This trapping behavior introduces a net directionality or asymmetry in the exciton dynamics as observed experimentally. year = 2024}, note = {PMID: 38427597}, keywords = {}, pubstate = {published}, tppubtype = {article} } Describing long-range energy transport is a crucial step, both toward deepening our knowledge on natural light-harvesting systems and toward developing novel photoactive materials. Here, we combine experiment and theory to resolve and reproduce energy transport on pico- to nanosecond time scales in single H-type supramolecular nanofibers based on carbonyl-bridged triarylamines (CBT). Each nanofiber shows energy transport dynamics over long distances up to ∼1 μm, despite exciton trapping at specific positions along the nanofibers. Using a minimal Frenkel exciton model including disorder, we demonstrate that spatial correlations in the normally distributed site energies are crucial to reproduce the experimental data. In particular, we can observe the long-range and subdiffusive nature of the exciton dynamics as well as the trapping behavior of excitons in specific locations of the nanofiber. This trapping behavior introduces a net directionality or asymmetry in the exciton dynamics as observed experimentally. year = 2024 |
| 12. | Shen, Guibin; Li, Xin; Zou, Yuqin; Dong, Hongye; Zhu, Dongping; Jiang, Yanglin; Ng, Xin Ren; Lin, Fen; Müller-Buschbaum, Peter; Mu, Cheng: High-Performance and Large-Area Inverted Perovskite Solar Cells Based on NiOx Films Enabled with A Novel Microstructure-Control Technology. In: Energy and Environmental Materials, 7 (1), 2024, ISSN: 25750348, (Cited by: 2; All Open Access, Hybrid Gold Open Access). (Type: Journal Article | Abstract | Links | BibTeX) @article{Shen2024, title = {High-Performance and Large-Area Inverted Perovskite Solar Cells Based on NiOx Films Enabled with A Novel Microstructure-Control Technology}, author = {Guibin Shen and Xin Li and Yuqin Zou and Hongye Dong and Dongping Zhu and Yanglin Jiang and Xin Ren Ng and Fen Lin and Peter Müller-Buschbaum and Cheng Mu}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85146311402&doi=10.1002%2feem2.12504&partnerID=40&md5=898f1a69605b2ff9be18105958ee4a77}, doi = {10.1002/eem2.12504}, issn = {25750348}, year = {2024}, date = {2024-01-01}, journal = {Energy and Environmental Materials}, volume = {7}, number = {1}, publisher = {John Wiley and Sons Inc}, abstract = {The improvement in the efficiency of inverted perovskite solar cells (PSCs) is significantly limited by undesirable contact at the NiOX/perovskite interface. In this study, a novel microstructure-control technology is proposed for fabrication of porous NiOX films using Pluronic P123 as the structure-directing agent and acetylacetone (AcAc) as the coordination agent. The synthesized porous NiOX films enhanced the hole extraction efficiency and reduced recombination defects at the NiOX/perovskite interface. Consequently, without any modification, the power conversion efficiency (PCE) of the PSC with MAPbI3 as the absorber layer improved from 16.50% to 19.08%. Moreover, the PCE of the device composed of perovskite Cs0.05(MA0.15FA0.85)0.95Pb(I0.85Br0.15)3 improved from 17.49% to 21.42%. Furthermore, the application of the fabricated porous NiOX on fluorine-doped tin oxide (FTO) substrates enabled the fabrication of large-area PSCs (1.2 cm2) with a PCE of 19.63%. This study provides a novel strategy for improving the contact at the NiOX/perovskite interface for the fabrication of high-performance large-area perovskite solar cells. © 2022 The Authors. Energy & Environmental Materials published by John Wiley & Sons Australia, Ltd on behalf of Zhengzhou University.}, note = {Cited by: 2; All Open Access, Hybrid Gold Open Access}, keywords = {}, pubstate = {published}, tppubtype = {article} } The improvement in the efficiency of inverted perovskite solar cells (PSCs) is significantly limited by undesirable contact at the NiOX/perovskite interface. In this study, a novel microstructure-control technology is proposed for fabrication of porous NiOX films using Pluronic P123 as the structure-directing agent and acetylacetone (AcAc) as the coordination agent. The synthesized porous NiOX films enhanced the hole extraction efficiency and reduced recombination defects at the NiOX/perovskite interface. Consequently, without any modification, the power conversion efficiency (PCE) of the PSC with MAPbI3 as the absorber layer improved from 16.50% to 19.08%. Moreover, the PCE of the device composed of perovskite Cs0.05(MA0.15FA0.85)0.95Pb(I0.85Br0.15)3 improved from 17.49% to 21.42%. Furthermore, the application of the fabricated porous NiOX on fluorine-doped tin oxide (FTO) substrates enabled the fabrication of large-area PSCs (1.2 cm2) with a PCE of 19.63%. This study provides a novel strategy for improving the contact at the NiOX/perovskite interface for the fabrication of high-performance large-area perovskite solar cells. © 2022 The Authors. Energy & Environmental Materials published by John Wiley & Sons Australia, Ltd on behalf of Zhengzhou University. |
| 13. | Zou, Yuqin; Song, Qili; Zhou, Jungui; Yin, Shanshan; Li, Yanan; Apfelbeck, Fabian A C; Zheng, Tianle; Fung, Man-Keung; Mu, Cheng; Müller-Buschbaum, Peter: Ammonium Sulfate to Modulate Crystallization for High-Performance Rigid and Flexible Perovskite Solar Cells. In: Small, 2024, ISSN: 16136810, (Cited by: 0). (Type: Journal Article | Abstract | Links | BibTeX) @article{Zou2024c, title = {Ammonium Sulfate to Modulate Crystallization for High-Performance Rigid and Flexible Perovskite Solar Cells}, author = {Yuqin Zou and Qili Song and Jungui Zhou and Shanshan Yin and Yanan Li and Fabian A C Apfelbeck and Tianle Zheng and Man-Keung Fung and Cheng Mu and Peter Müller-Buschbaum}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85191834414&doi=10.1002%2fsmll.202401456&partnerID=40&md5=f3bb1a2131cb975eaa85d793053bbed2}, doi = {10.1002/smll.202401456}, issn = {16136810}, year = {2024}, date = {2024-01-01}, journal = {Small}, publisher = {John Wiley and Sons Inc}, abstract = {Perovskite solar cells (PSCs) are attracting widespread research and attention as highly promising candidates in the field of electronic photovoltaics owing to their exceptional power conversion efficiency (PCE). However, rigid or flexible PSCs still face challenges in preparing full-coverage and low-defect perovskite films, as well as achieving highly reproducible and highly stable devices. Herein, a multifunctional additive 2-aminoethyl hydrogen sulfate (AES) is designed to regulate the film crystallization and thereby form flat and pinhole-free perovskite films. It is found that the introduction of AES can effectively passivate defects, restrain charge carrier recombination, and then achieve a higher fill factor. As seen with grazing incidence wide-angle X-ray scattering (GIWAXS), this approach does not affect the crystal orientation distribution. It is observed that AES addition shows a universality across different perovskite components since the PCE is improved up to 20.7% for FA0.97MA0.03Pb(I0.97Br0.03)3-AES, 22.85% for Cs0.05FA0.95PbI3-AES, 22.23% for FAPbI2.7Br0.3-AES, and 23.32% for FAPI-AES rigid devices. Remarkably, the non-encapsulated flexible Cs0.05 (FA0.85MA0.15)0.95Pb(I0.85Br0.15)3 device with AES additive delivers a PCE of 20.1% and maintains over 97% of its initial efficiency under ambient conditions (25 ± 5% relative humidity) over 2280 h of aging. © 2024 The Authors. Small published by Wiley-VCH GmbH.}, note = {Cited by: 0}, keywords = {}, pubstate = {published}, tppubtype = {article} } Perovskite solar cells (PSCs) are attracting widespread research and attention as highly promising candidates in the field of electronic photovoltaics owing to their exceptional power conversion efficiency (PCE). However, rigid or flexible PSCs still face challenges in preparing full-coverage and low-defect perovskite films, as well as achieving highly reproducible and highly stable devices. Herein, a multifunctional additive 2-aminoethyl hydrogen sulfate (AES) is designed to regulate the film crystallization and thereby form flat and pinhole-free perovskite films. It is found that the introduction of AES can effectively passivate defects, restrain charge carrier recombination, and then achieve a higher fill factor. As seen with grazing incidence wide-angle X-ray scattering (GIWAXS), this approach does not affect the crystal orientation distribution. It is observed that AES addition shows a universality across different perovskite components since the PCE is improved up to 20.7% for FA0.97MA0.03Pb(I0.97Br0.03)3-AES, 22.85% for Cs0.05FA0.95PbI3-AES, 22.23% for FAPbI2.7Br0.3-AES, and 23.32% for FAPI-AES rigid devices. Remarkably, the non-encapsulated flexible Cs0.05 (FA0.85MA0.15)0.95Pb(I0.85Br0.15)3 device with AES additive delivers a PCE of 20.1% and maintains over 97% of its initial efficiency under ambient conditions (25 ± 5% relative humidity) over 2280 h of aging. © 2024 The Authors. Small published by Wiley-VCH GmbH. |
| 14. | Kang, Ziyong; Wang, Kun; Zhang, Lu; Yang, Yang; Wu, Jiandong; Tong, Yu; Yan, Peng; Chen, Yali; Qi, Heng; Sun, Kun; Müller-Buschbaum, Peter; Zhang, Xuewen; Shang, Jingzhi; Wang, Hongqiang: Homogenizing The Low-Dimensional Phases for Stable 2D-3D Tin Perovskite Solar Cells. In: Small, 2024, ISSN: 16136810, (Cited by: 0). (Type: Journal Article | Abstract | Links | BibTeX) @article{Kang2024c, title = {Homogenizing The Low-Dimensional Phases for Stable 2D-3D Tin Perovskite Solar Cells}, author = {Ziyong Kang and Kun Wang and Lu Zhang and Yang Yang and Jiandong Wu and Yu Tong and Peng Yan and Yali Chen and Heng Qi and Kun Sun and Peter Müller-Buschbaum and Xuewen Zhang and Jingzhi Shang and Hongqiang Wang}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85197519682&doi=10.1002%2fsmll.202402028&partnerID=40&md5=596cfebd32154af1fbc81a021fabdbc5}, doi = {10.1002/smll.202402028}, issn = {16136810}, year = {2024}, date = {2024-01-01}, journal = {Small}, publisher = {John Wiley and Sons Inc}, abstract = {2D-3D tin-based perovskites are considered as promising candidates for achieving efficient lead-free perovskite solar cells (PSCs). However, the existence of multiple low-dimensional phases formed during the film preparation hinders the efficient transport of charge carriers. In addition, the non-homogeneous distribution of low-dimensional phases leads to lattice distortion and increases the defect density, which are undesirable for the stability of tin-based PSCs. Here, mixed spacer cations [diethylamine (DEA+) and phenethylamine (PEA+)] are introduced into tin perovskite films to modulate the distribution of the 2D phases. It is found that compared to the film with only PEA+, the combination of DEA+ and PEA+ favors the formation of homogeneous low-dimensional perovskite phases with three octahedral monolayers (n = 3), especially near the bottom interface between perovskite and hole transport layer. The homogenization of 2D phases help improve the film quality with reduced lattice distortion and released strain. With these merits, the tin PSC shows significantly improved stability with 94% of its initial efficiency retained after storing in a nitrogen atmosphere for over 4600 h, and over 80% efficiency maintained after continuous illumination for 400 h. © 2024 Wiley-VCH GmbH.}, note = {Cited by: 0}, keywords = {}, pubstate = {published}, tppubtype = {article} } 2D-3D tin-based perovskites are considered as promising candidates for achieving efficient lead-free perovskite solar cells (PSCs). However, the existence of multiple low-dimensional phases formed during the film preparation hinders the efficient transport of charge carriers. In addition, the non-homogeneous distribution of low-dimensional phases leads to lattice distortion and increases the defect density, which are undesirable for the stability of tin-based PSCs. Here, mixed spacer cations [diethylamine (DEA+) and phenethylamine (PEA+)] are introduced into tin perovskite films to modulate the distribution of the 2D phases. It is found that compared to the film with only PEA+, the combination of DEA+ and PEA+ favors the formation of homogeneous low-dimensional perovskite phases with three octahedral monolayers (n = 3), especially near the bottom interface between perovskite and hole transport layer. The homogenization of 2D phases help improve the film quality with reduced lattice distortion and released strain. With these merits, the tin PSC shows significantly improved stability with 94% of its initial efficiency retained after storing in a nitrogen atmosphere for over 4600 h, and over 80% efficiency maintained after continuous illumination for 400 h. © 2024 Wiley-VCH GmbH. |
| 15. | Arslanova, Ksenija; Ganswindt, Patrick; Lorenzen, Tizian; Kostyurina, Ekaterina; Karaghiosoff, Konstantin; Nickel, Bert; Müller-Caspary, Knut; Urban, Alexander S: Synthesis of Cs3Cu2I5 Nanocrystals in a Continuous Flow System. In: Small, 2024, ISSN: 16136810, (Cited by: 0; All Open Access, Hybrid Gold Open Access). (Type: Journal Article | Abstract | Links | BibTeX) @article{Arslanova2024, title = {Synthesis of Cs3Cu2I5 Nanocrystals in a Continuous Flow System}, author = {Ksenija Arslanova and Patrick Ganswindt and Tizian Lorenzen and Ekaterina Kostyurina and Konstantin Karaghiosoff and Bert Nickel and Knut Müller-Caspary and Alexander S Urban}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85198390458&doi=10.1002%2fsmll.202403572&partnerID=40&md5=00d5643d09a0ac08b39bce2f64dec47c}, doi = {10.1002/smll.202403572}, issn = {16136810}, year = {2024}, date = {2024-01-01}, journal = {Small}, publisher = {John Wiley and Sons Inc}, abstract = {Achieving the goal of generating all of the world's energy via renewable sources and significantly reducing the energy usage will require the development of novel, abundant, nontoxic energy conversion materials. Here, a cost-efficient and scalable continuous flow synthesis of Cs3Cu2I5 nanocrystals is developed as a basis for the rapid advancement of novel nanomaterials. Ideal precursor solutions are obtained through a novel batch synthesis, whose product served as a benchmark for the subsequent flow synthesis. Realizing this setup enabled a reproducible fabrication of Cs3Cu2I5 nanocrystals. The effect of volumetric flow rate and temperature on the final product's morphology and optical properties are determined, obtaining 21% quantum yield with the optimal configuration. Consequently, the size and morphology of the nanocrystals can be tuned with far more precision and in a much broader range than previously achievable. The flow setup is readily applicable to other relevant nanomaterials. It should enable a rapid determination of a material's potential and subsequently optimize its desired properties for renewable energy generation or efficient optoelectronics. © 2024 The Author(s). Small published by Wiley-VCH GmbH.}, note = {Cited by: 0; All Open Access, Hybrid Gold Open Access}, keywords = {}, pubstate = {published}, tppubtype = {article} } Achieving the goal of generating all of the world's energy via renewable sources and significantly reducing the energy usage will require the development of novel, abundant, nontoxic energy conversion materials. Here, a cost-efficient and scalable continuous flow synthesis of Cs3Cu2I5 nanocrystals is developed as a basis for the rapid advancement of novel nanomaterials. Ideal precursor solutions are obtained through a novel batch synthesis, whose product served as a benchmark for the subsequent flow synthesis. Realizing this setup enabled a reproducible fabrication of Cs3Cu2I5 nanocrystals. The effect of volumetric flow rate and temperature on the final product's morphology and optical properties are determined, obtaining 21% quantum yield with the optimal configuration. Consequently, the size and morphology of the nanocrystals can be tuned with far more precision and in a much broader range than previously achievable. The flow setup is readily applicable to other relevant nanomaterials. It should enable a rapid determination of a material's potential and subsequently optimize its desired properties for renewable energy generation or efficient optoelectronics. © 2024 The Author(s). Small published by Wiley-VCH GmbH. |
| 16. | Zhang, Kaicheng; Liu, Chao; Peng, Zijian; Li, Chaohui; Tian, Jingjing; Li, Canru; Cerrillo, José Garcia; Dong, Lirong; Streller, Fabian; Späth, Andreas; Musiienko, Artem; Englhard, Jonas; Li, Ning; Zhang, Jiyun; Du, Tian; Sathasivam, Sanjayan; Macdonald, Thomas J; These, Albert; Corre, Vincent Le M; Forberich, Karen; Meng, Wei; Fink, Rainer H; Osvet, Andres; Lüer, Larry; Bachmann, Julien; Tong, Jinhui; Brabec, Christoph J: Binary cations minimize energy loss in the wide-band-gap perovskite toward efficient all-perovskite tandem solar cells. In: Joule, 2024, ISSN: 25424351, (Cited by: 0). (Type: Journal Article | Abstract | Links | BibTeX) @article{Zhang2024c, title = {Binary cations minimize energy loss in the wide-band-gap perovskite toward efficient all-perovskite tandem solar cells}, author = {Kaicheng Zhang and Chao Liu and Zijian Peng and Chaohui Li and Jingjing Tian and Canru Li and José Garcia Cerrillo and Lirong Dong and Fabian Streller and Andreas Späth and Artem Musiienko and Jonas Englhard and Ning Li and Jiyun Zhang and Tian Du and Sanjayan Sathasivam and Thomas J Macdonald and Albert These and Vincent M Le Corre and Karen Forberich and Wei Meng and Rainer H Fink and Andres Osvet and Larry Lüer and Julien Bachmann and Jinhui Tong and Christoph J Brabec}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85201705955&doi=10.1016%2fj.joule.2024.07.003&partnerID=40&md5=4f7fd2d1af7276ca125d440e37938fe5}, doi = {10.1016/j.joule.2024.07.003}, issn = {25424351}, year = {2024}, date = {2024-01-01}, journal = {Joule}, publisher = {Cell Press}, abstract = {Perovskite-based tandem solar cells stand at the forefront of photovoltaic innovation due to their exceptional performance and cost-effective fabrication. This study focuses on minimizing energy losses within a 1.80 eV perovskite sub-cell. We demonstrate that the surface treatment of perovskite with binary guanidinium bromide and 4-fluorophenylammonium iodide synergistically reduces defect densities and adjusts interfacial energy-level alignment. The enhanced passivation effect and the formation of a surface dipole significantly reduce nonradiative recombination and transport losses, leading to a notable increase in the open-circuit voltage and fill factor product, thereby achieving an impressive power conversion efficiency (PCE) of 19.0%. The reproducibility of these findings is confirmed by consistent results across different laboratories. Furthermore, integration with a narrow-band-gap perovskite yields an all-perovskite tandem device with a PCE of 27.2%. This comprehensive understanding of the pivotal role of spacer cations in surface treatment significantly advances the pathway toward efficient perovskite photovoltaics. © 2024 Elsevier Inc.}, note = {Cited by: 0}, keywords = {}, pubstate = {published}, tppubtype = {article} } Perovskite-based tandem solar cells stand at the forefront of photovoltaic innovation due to their exceptional performance and cost-effective fabrication. This study focuses on minimizing energy losses within a 1.80 eV perovskite sub-cell. We demonstrate that the surface treatment of perovskite with binary guanidinium bromide and 4-fluorophenylammonium iodide synergistically reduces defect densities and adjusts interfacial energy-level alignment. The enhanced passivation effect and the formation of a surface dipole significantly reduce nonradiative recombination and transport losses, leading to a notable increase in the open-circuit voltage and fill factor product, thereby achieving an impressive power conversion efficiency (PCE) of 19.0%. The reproducibility of these findings is confirmed by consistent results across different laboratories. Furthermore, integration with a narrow-band-gap perovskite yields an all-perovskite tandem device with a PCE of 27.2%. This comprehensive understanding of the pivotal role of spacer cations in surface treatment significantly advances the pathway toward efficient perovskite photovoltaics. © 2024 Elsevier Inc. |
| 17. | Aigner, Andreas; Weber, Thomas; Wester, Alwin; Maier, Stefan A; Tittl, Andreas: Continuous spectral and coupling-strength encoding with dual-gradient metasurfaces. In: Nature Nanotechnology, 2024, ISSN: 17483387, (Cited by: 0; All Open Access, Hybrid Gold Open Access). (Type: Journal Article | Abstract | Links | BibTeX) @article{Aigner2024b, title = {Continuous spectral and coupling-strength encoding with dual-gradient metasurfaces}, author = {Andreas Aigner and Thomas Weber and Alwin Wester and Stefan A Maier and Andreas Tittl}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85202055547&doi=10.1038%2fs41565-024-01767-2&partnerID=40&md5=42bcf5a02280697e22de3f6008310232}, doi = {10.1038/s41565-024-01767-2}, issn = {17483387}, year = {2024}, date = {2024-01-01}, journal = {Nature Nanotechnology}, publisher = {Nature Research}, abstract = {To control and enhance light–matter interactions at the nanoscale, two parameters are central: the spectral overlap between an optical cavity mode and the material’s spectral features (for example, excitonic or molecular absorption lines), and the quality factor of the cavity. Controlling both parameters simultaneously would enable the investigation of systems with complex spectral features, such as multicomponent molecular mixtures or heterogeneous solid-state materials. So far, it has been possible only to sample a limited set of data points within this two-dimensional parameter space. Here we introduce a nanophotonic approach that can simultaneously and continuously encode the spectral and quality-factor parameter space within a compact spatial area. We use a dual-gradient metasurface design composed of a two-dimensional array of smoothly varying subwavelength nanoresonators, each supporting a unique mode based on symmetry-protected bound states in the continuum. This results in 27,500 distinct modes and a mode density approaching the theoretical upper limit for metasurfaces. By applying our platform to surface-enhanced molecular spectroscopy, we find that the optimal quality factor for maximum sensitivity depends on the amount of analyte, enabling effective molecular detection regardless of analyte concentration within a single dual-gradient metasurface. Our design provides a method to analyse the complete spectral and coupling-strength parameter space of complex material systems for applications such as photocatalysis, chemical sensing and entangled photon generation. © The Author(s) 2024.}, note = {Cited by: 0; All Open Access, Hybrid Gold Open Access}, keywords = {}, pubstate = {published}, tppubtype = {article} } To control and enhance light–matter interactions at the nanoscale, two parameters are central: the spectral overlap between an optical cavity mode and the material’s spectral features (for example, excitonic or molecular absorption lines), and the quality factor of the cavity. Controlling both parameters simultaneously would enable the investigation of systems with complex spectral features, such as multicomponent molecular mixtures or heterogeneous solid-state materials. So far, it has been possible only to sample a limited set of data points within this two-dimensional parameter space. Here we introduce a nanophotonic approach that can simultaneously and continuously encode the spectral and quality-factor parameter space within a compact spatial area. We use a dual-gradient metasurface design composed of a two-dimensional array of smoothly varying subwavelength nanoresonators, each supporting a unique mode based on symmetry-protected bound states in the continuum. This results in 27,500 distinct modes and a mode density approaching the theoretical upper limit for metasurfaces. By applying our platform to surface-enhanced molecular spectroscopy, we find that the optimal quality factor for maximum sensitivity depends on the amount of analyte, enabling effective molecular detection regardless of analyte concentration within a single dual-gradient metasurface. Our design provides a method to analyse the complete spectral and coupling-strength parameter space of complex material systems for applications such as photocatalysis, chemical sensing and entangled photon generation. © The Author(s) 2024. |
| 18. | Hungenberg, Julian; Hochgesang, Adrian; Meichsner, Florian; Thelakkat, Mukundan: Self-Doped Mixed Ionic-Electronic Conductors to Tune the Threshold Voltage and the Mode of Operation in Organic Electrochemical Transistors. In: Advanced Functional Materials, 2024, ISSN: 1616301X, (Cited by: 0; All Open Access, Hybrid Gold Open Access). (Type: Journal Article | Abstract | Links | BibTeX) @article{Hungenberg2024, title = {Self-Doped Mixed Ionic-Electronic Conductors to Tune the Threshold Voltage and the Mode of Operation in Organic Electrochemical Transistors}, author = {Julian Hungenberg and Adrian Hochgesang and Florian Meichsner and Mukundan Thelakkat}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85199366751&doi=10.1002%2fadfm.202407067&partnerID=40&md5=e507f7fe2d70666e3bcced9838e54c3b}, doi = {10.1002/adfm.202407067}, issn = {1616301X}, year = {2024}, date = {2024-01-01}, journal = {Advanced Functional Materials}, publisher = {John Wiley and Sons Inc}, abstract = {Organic mixed ionic-electronic conductors with tunable doping, low threshold voltages, and air stability are crucial for bioelectronic applications. A homopolymer based on an alkoxy thiophene monomer and its copolymer with a thiophene carrying ethylene glycol side chains are synthesized and converted to self-doped conjugated polyelectrolytes, P3HOTS-TMA+, and P3HOTS-TMA+-co-P3MEEET. The self-doping occurs during the conversion to polyelectrolytes. Both polyelectrolytes show high electrical conductivity without any external dopants. UV–Vis–NIR spectroscopy and spectroelectrochemistry confirm excellent air stability of the doped state. In an organic electrochemical transistor (OECT), the P3HOTS-TMA+ operates in depletion mode, while P3HOTS-TMA+-co-P3MEEET exhibits accumulation mode of operation with low threshold voltage, both showing fast response times. On the other hand, the non-doped homopolymer, P3MEEET, shows a high negative threshold voltage in accumulation mode. Thus, copolymerization with the self-dopable monomer changes the mode of operation as well as the threshold voltage substantially. Ultraviolet photoelectron spectroscopy reveals a considerable reduction of the hole injection barrier for the self-doped system P3HOTS-TMA+. Mott-Schottky analysis shows reduction in charge carrier concentration in the copolymer compared to the homopolymer. Thus, the copolymerization strategy with a self-dopable monomer is an efficient tool for tuning the degree of doping leading to low threshold voltage in OECTs. © 2024 The Author(s). Advanced Functional Materials published by Wiley-VCH GmbH.}, note = {Cited by: 0; All Open Access, Hybrid Gold Open Access}, keywords = {}, pubstate = {published}, tppubtype = {article} } Organic mixed ionic-electronic conductors with tunable doping, low threshold voltages, and air stability are crucial for bioelectronic applications. A homopolymer based on an alkoxy thiophene monomer and its copolymer with a thiophene carrying ethylene glycol side chains are synthesized and converted to self-doped conjugated polyelectrolytes, P3HOTS-TMA+, and P3HOTS-TMA+-co-P3MEEET. The self-doping occurs during the conversion to polyelectrolytes. Both polyelectrolytes show high electrical conductivity without any external dopants. UV–Vis–NIR spectroscopy and spectroelectrochemistry confirm excellent air stability of the doped state. In an organic electrochemical transistor (OECT), the P3HOTS-TMA+ operates in depletion mode, while P3HOTS-TMA+-co-P3MEEET exhibits accumulation mode of operation with low threshold voltage, both showing fast response times. On the other hand, the non-doped homopolymer, P3MEEET, shows a high negative threshold voltage in accumulation mode. Thus, copolymerization with the self-dopable monomer changes the mode of operation as well as the threshold voltage substantially. Ultraviolet photoelectron spectroscopy reveals a considerable reduction of the hole injection barrier for the self-doped system P3HOTS-TMA+. Mott-Schottky analysis shows reduction in charge carrier concentration in the copolymer compared to the homopolymer. Thus, the copolymerization strategy with a self-dopable monomer is an efficient tool for tuning the degree of doping leading to low threshold voltage in OECTs. © 2024 The Author(s). Advanced Functional Materials published by Wiley-VCH GmbH. |
| 19. | Sun, Kun; Guo, Renjun; Liu, Shangpu; Guo, Dengyang; Jiang, Xiongzhuo; Huber, Linus F; Liang, Yuxin; Reus, Manuel A; Li, Zerui; Guan, Tianfu; Zhou, Jungui; Schwartzkopf, Matthias; Stranks, Samuel D; Deschler, Felix; Müller-Buschbaum, Peter: Deciphering Structure and Charge Carrier Behavior in Reduced-Dimensional Perovskites. In: Advanced Functional Materials, 2024, ISSN: 1616301X, (Cited by: 0; All Open Access, Hybrid Gold Open Access). (Type: Journal Article | Abstract | Links | BibTeX) @article{Sun2024, title = {Deciphering Structure and Charge Carrier Behavior in Reduced-Dimensional Perovskites}, author = {Kun Sun and Renjun Guo and Shangpu Liu and Dengyang Guo and Xiongzhuo Jiang and Linus F Huber and Yuxin Liang and Manuel A Reus and Zerui Li and Tianfu Guan and Jungui Zhou and Matthias Schwartzkopf and Samuel D Stranks and Felix Deschler and Peter Müller-Buschbaum}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85202489750&doi=10.1002%2fadfm.202411153&partnerID=40&md5=cf3c95c8ed46c49393ce0f5de0f64520}, doi = {10.1002/adfm.202411153}, issn = {1616301X}, year = {2024}, date = {2024-01-01}, journal = {Advanced Functional Materials}, publisher = {John Wiley and Sons Inc}, abstract = {Reduced-dimensional perovskites (RDPs) have advanced perovskite optoelectronic devices due to their tunable energy landscape, structure, and orientation. However, the origin of structural and photophysical property changes when moving from low-dimensional to high-dimensional RDPs remains to be understood. This study systematically reveals structural and photophysical properties of slot-die-coated Dion-Jacobson (DJ) and Ruddlesden-Popper (RP) RDPs with different dimensionalities. RP RDPs with lower dimensionality (n = 2) exhibit a dominant n = 2 phase, preferential out-of-plane orientation, and longer charge carrier lifetime compared with DJ RDPs. In addition, the formation kinetics of RDPs with higher dimensionality (n = 4) are unraveled by in situ X-ray scattering, showing the favorable formation of the lower-n phase in RP RDPs. The formation of these lower-n phases is thermodynamically and stoichiometrically favored, while these phases are likely in the form of an “intermediate phase” which bridges the 3D-like and lower-n phases in DJ RDPs. DJ RDPs with higher dimensionality demonstrate comparable phase purity, preferential orientation, spatially vertical phase homogeneity, and longer charge carrier lifetime. As such, DJ-based perovskite solar cells (PSCs) (n = 4) demonstrate better photostability under operational conditions than RP-based PSCs. Thus, the work paves the way for the utilization of RDPs to upscale PSCs. © 2024 The Author(s). Advanced Functional Materials published by Wiley-VCH GmbH.}, note = {Cited by: 0; All Open Access, Hybrid Gold Open Access}, keywords = {}, pubstate = {published}, tppubtype = {article} } Reduced-dimensional perovskites (RDPs) have advanced perovskite optoelectronic devices due to their tunable energy landscape, structure, and orientation. However, the origin of structural and photophysical property changes when moving from low-dimensional to high-dimensional RDPs remains to be understood. This study systematically reveals structural and photophysical properties of slot-die-coated Dion-Jacobson (DJ) and Ruddlesden-Popper (RP) RDPs with different dimensionalities. RP RDPs with lower dimensionality (n = 2) exhibit a dominant n = 2 phase, preferential out-of-plane orientation, and longer charge carrier lifetime compared with DJ RDPs. In addition, the formation kinetics of RDPs with higher dimensionality (n = 4) are unraveled by in situ X-ray scattering, showing the favorable formation of the lower-n phase in RP RDPs. The formation of these lower-n phases is thermodynamically and stoichiometrically favored, while these phases are likely in the form of an “intermediate phase” which bridges the 3D-like and lower-n phases in DJ RDPs. DJ RDPs with higher dimensionality demonstrate comparable phase purity, preferential orientation, spatially vertical phase homogeneity, and longer charge carrier lifetime. As such, DJ-based perovskite solar cells (PSCs) (n = 4) demonstrate better photostability under operational conditions than RP-based PSCs. Thus, the work paves the way for the utilization of RDPs to upscale PSCs. © 2024 The Author(s). Advanced Functional Materials published by Wiley-VCH GmbH. |
| 20. | Li, Zerui; Li, Yunan; Zhang, Jinsheng; Guo, Renjun; Sun, Kun; Jiang, Xiongzhuo; Wang, Peixi; Tu, Suo; Schwartzkopf, Matthias; Li, Zhiyun; Ma, Chang-Qi; Müller-Buschbaum, Peter: Suppressed Degradation Process of Green-Solvent Based Organic Solar Cells Through ZnO Modification With Sulfhydryl Derivatives. In: Advanced Energy Materials, 2024, ISSN: 16146832, (Cited by: 0; All Open Access, Hybrid Gold Open Access). (Type: Journal Article | Abstract | Links | BibTeX) @article{Li2024e, title = {Suppressed Degradation Process of Green-Solvent Based Organic Solar Cells Through ZnO Modification With Sulfhydryl Derivatives}, author = {Zerui Li and Yunan Li and Jinsheng Zhang and Renjun Guo and Kun Sun and Xiongzhuo Jiang and Peixi Wang and Suo Tu and Matthias Schwartzkopf and Zhiyun Li and Chang-Qi Ma and Peter Müller-Buschbaum}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85202596295&doi=10.1002%2faenm.202402920&partnerID=40&md5=db8ab8d81b70ecba894744a882d82441}, doi = {10.1002/aenm.202402920}, issn = {16146832}, year = {2024}, date = {2024-01-01}, journal = {Advanced Energy Materials}, publisher = {John Wiley and Sons Inc}, abstract = {The interface of organic solar cells plays a crucial role in device performance and stability. Several investigations demonstrated that the interface will affect the morphology and microstructure of the active layer, which is important for device performance. Here, several mercaptan derivatives are explored in green-solvent based organic solar cells (PBDB-TF-T1: BTP-4F-12) as effective stabilization modifiers on ZnO. Operando grazing-incidence wide/small-angle X-ray scattering (GIWAXS/GISAXS) provides a deep understanding of the degradation process during operation. The degradation process is driven by a compression of the molecule stacking as well as a decrease in the donor crystallinity, besides the known decomposition of the acceptor at the interface. Solar cell degradation comprises three stages, where an unexpected component from the acceptor appears in the second stage, simultaneously with a shapely shrinking micro-structure. Furthermore, the interface modifier pentaerythritol tetrakis(3-mercapto-propionate) (PETMP) stabilizes the crystallinity of the donor as well as suppresses the decomposition of the acceptor, thus improving the device stability. The modification effect is caused by the interaction between Zn and S from the sulfhydryl groups of the mercaptan derivatives. Thus, studies of changes in the active layer morphology extend the knowledge from ex situ characterizations, broadening the understanding of the degradation mechanisms. © 2024 The Author(s). Advanced Energy Materials published by Wiley-VCH GmbH.}, note = {Cited by: 0; All Open Access, Hybrid Gold Open Access}, keywords = {}, pubstate = {published}, tppubtype = {article} } The interface of organic solar cells plays a crucial role in device performance and stability. Several investigations demonstrated that the interface will affect the morphology and microstructure of the active layer, which is important for device performance. Here, several mercaptan derivatives are explored in green-solvent based organic solar cells (PBDB-TF-T1: BTP-4F-12) as effective stabilization modifiers on ZnO. Operando grazing-incidence wide/small-angle X-ray scattering (GIWAXS/GISAXS) provides a deep understanding of the degradation process during operation. The degradation process is driven by a compression of the molecule stacking as well as a decrease in the donor crystallinity, besides the known decomposition of the acceptor at the interface. Solar cell degradation comprises three stages, where an unexpected component from the acceptor appears in the second stage, simultaneously with a shapely shrinking micro-structure. Furthermore, the interface modifier pentaerythritol tetrakis(3-mercapto-propionate) (PETMP) stabilizes the crystallinity of the donor as well as suppresses the decomposition of the acceptor, thus improving the device stability. The modification effect is caused by the interaction between Zn and S from the sulfhydryl groups of the mercaptan derivatives. Thus, studies of changes in the active layer morphology extend the knowledge from ex situ characterizations, broadening the understanding of the degradation mechanisms. © 2024 The Author(s). Advanced Energy Materials published by Wiley-VCH GmbH. |
References (last update: Sept. 23, 2024):
2025 |
Akram, Sahar Javaid; Meißner, Sophie; Kümmel, Stephan Analyzing Electronic Excitations and Exciton Binding Energies in Y6 Films Journal Article Advanced Functional Materials, n/a (n/a), pp. 2419236, 2025, ISSN: 1616-3028 . Abstract | Links | BibTeX | Tags: density functional theory, exciton binding energies, optimal tuning, screened range separated hybrid, Y6 molecules @article{https://doi.org/10.1002/adfm.202419236, title = {Analyzing Electronic Excitations and Exciton Binding Energies in Y6 Films}, author = {Sahar Javaid Akram and Sophie Meißner and Stephan Kümmel}, url = {https://advanced.onlinelibrary.wiley.com/doi/abs/10.1002/adfm.202419236}, doi = {https://doi.org/10.1002/adfm.202419236}, issn = {1616-3028 }, year = {2025}, date = {2025-02-21}, journal = {Advanced Functional Materials}, volume = {n/a}, number = {n/a}, pages = {2419236}, abstract = {Abstract The Y6 molecule is one of the most promising non-fullerene acceptors. Based on first-principles calculations, this paper analyzes how the separation of an electronic excitation into electron and hole densities is influenced by the interaction between different Y6 molecules. By calculating the optical and the fundamental gaps of ensembles of Y6 molecules that realistically represent a film, their corresponding exciton binding energies are obtained. The combination of range separation, optimal tuning, and dielectric screening endows the presented density functional theory calculations with predictive power. The calculations reveal that the electronic excitations, characterized as electron–hole pairs via their natural transition orbitals, spread across multiple Y6 molecules. A distinct decrease in the exciton binding energy is correlated to a notable charge separation, and the exciton binding energy saturates in ensembles of six to seven Y6 molecules at ≈0.25 electronvolt (eV). These findings contribute to explaining the efficient charge separation in films of Y6. They also give a guideline for the number of molecules that theoretical models should take into account when they aim at a realistic description of charge separation.}, keywords = {density functional theory, exciton binding energies, optimal tuning, screened range separated hybrid, Y6 molecules}, pubstate = {published}, tppubtype = {article} } Abstract The Y6 molecule is one of the most promising non-fullerene acceptors. Based on first-principles calculations, this paper analyzes how the separation of an electronic excitation into electron and hole densities is influenced by the interaction between different Y6 molecules. By calculating the optical and the fundamental gaps of ensembles of Y6 molecules that realistically represent a film, their corresponding exciton binding energies are obtained. The combination of range separation, optimal tuning, and dielectric screening endows the presented density functional theory calculations with predictive power. The calculations reveal that the electronic excitations, characterized as electron–hole pairs via their natural transition orbitals, spread across multiple Y6 molecules. A distinct decrease in the exciton binding energy is correlated to a notable charge separation, and the exciton binding energy saturates in ensembles of six to seven Y6 molecules at ≈0.25 electronvolt (eV). These findings contribute to explaining the efficient charge separation in films of Y6. They also give a guideline for the number of molecules that theoretical models should take into account when they aim at a realistic description of charge separation. |
Kuhn, Meike; Wenzel, Felix A; Greve, Christopher; Kreger, Klaus; Schwartzkopf, Matthias; Schmidt, Hans-Werner; Grüninger, Helen; Herzig, Eva M Tailored Supramolecular Additives to Control the Crystallization Process and Morphology of MAPbI3 Journal Article Small, 21 (9), pp. 2410230, 2025, ISSN: 1613-6810. Abstract | Links | BibTeX | Tags: additive engineering, crystal morphology, crystallization control, GIWAXS, perovskites, solid-state NMR spectroscopy, supramolecular additive @article{Kuhn2025, title = {Tailored Supramolecular Additives to Control the Crystallization Process and Morphology of MAPbI3}, author = {Meike Kuhn and Felix A Wenzel and Christopher Greve and Klaus Kreger and Matthias Schwartzkopf and Hans-Werner Schmidt and Helen Grüninger and Eva M Herzig}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/smll.202410230}, doi = {https://doi.org/10.1002/smll.202410230}, issn = {1613-6810}, year = {2025}, date = {2025-02-05}, journal = {Small}, volume = {21}, number = {9}, pages = {2410230}, abstract = {Abstract Perovskite films feature unique optoelectronic properties, rendering them promising for electronic devices. The properties depend on the morphology on a broad range of length scales from nanometers to millimeters, influenced by a variety of factors. However, controlling the morphology is challenging. A tailored supramolecular additive, N, N’-bis(2-aminoethyl) terephthalamide is developed to control the intermediate and perovskite crystallization of methyl ammonium lead iodide (MAPbI3) and enhance the thermal and moisture stability in the final film. Reversible coordinative interactions of the carbonyl groups with Pb2+ ions via Lewis acid-base adduct and subsequent ion–ion interactions of the peripheral ammonium groups with the perovskite grain boundaries are combined which is stabilized by a strong hydrogen bonding pattern formed between the amide moieties of the additive molecules. Adding low amounts of this additive to the precursor solution significantly decelerates the structure formation and systematically reduces the crystallite size. Slower growth of the intermediate phases and the incorporation of the additive to the grain boundary is observed with multiple time-resolved techniques. Evidence for the formation of single-molecule interlayers between the MAPbI3 crystals and the presence of directed supramolecular interaction between additive molecules is shown. Transferability of this approach to other perovskites is anticipated, paving the way to improved processing control and stability.}, keywords = {additive engineering, crystal morphology, crystallization control, GIWAXS, perovskites, solid-state NMR spectroscopy, supramolecular additive}, pubstate = {published}, tppubtype = {article} } Abstract Perovskite films feature unique optoelectronic properties, rendering them promising for electronic devices. The properties depend on the morphology on a broad range of length scales from nanometers to millimeters, influenced by a variety of factors. However, controlling the morphology is challenging. A tailored supramolecular additive, N, N’-bis(2-aminoethyl) terephthalamide is developed to control the intermediate and perovskite crystallization of methyl ammonium lead iodide (MAPbI3) and enhance the thermal and moisture stability in the final film. Reversible coordinative interactions of the carbonyl groups with Pb2+ ions via Lewis acid-base adduct and subsequent ion–ion interactions of the peripheral ammonium groups with the perovskite grain boundaries are combined which is stabilized by a strong hydrogen bonding pattern formed between the amide moieties of the additive molecules. Adding low amounts of this additive to the precursor solution significantly decelerates the structure formation and systematically reduces the crystallite size. Slower growth of the intermediate phases and the incorporation of the additive to the grain boundary is observed with multiple time-resolved techniques. Evidence for the formation of single-molecule interlayers between the MAPbI3 crystals and the presence of directed supramolecular interaction between additive molecules is shown. Transferability of this approach to other perovskites is anticipated, paving the way to improved processing control and stability. |
Kutter, Maximilian; Hilgert, Annika; Maier, Maximilian; Schilling, Monja; Greve, Christopher R; Loukrakpam, Rameshwori; Hagemeier, Wiebke; Rosin, Andreas; Muggli, Mark; Herzig, Eva M; Zeis, Roswitha; Böhm, Thomas; Gerdes, Thorsten; Roth, Christina LiF@PFSA-Based Composite Membranes for PEM Fuel Cells at Intermediate Temperature Conditions Journal Article ACS Applied Polymer Materials, 7 (2), pp. 599–610, 2025. Abstract | Links | BibTeX | Tags: @article{Kutter2025, title = {LiF@PFSA-Based Composite Membranes for PEM Fuel Cells at Intermediate Temperature Conditions}, author = {Maximilian Kutter and Annika Hilgert and Maximilian Maier and Monja Schilling and Christopher R Greve and Rameshwori Loukrakpam and Wiebke Hagemeier and Andreas Rosin and Mark Muggli and Eva M Herzig and Roswitha Zeis and Thomas Böhm and Thorsten Gerdes and Christina Roth}, url = {https://doi.org/10.1021/acsapm.4c02540}, doi = {10.1021/acsapm.4c02540}, year = {2025}, date = {2025-01-05}, journal = {ACS Applied Polymer Materials}, volume = {7}, number = {2}, pages = {599–610}, abstract = {Polymer electrolyte membrane fuel cells (PEMFCs) operating at temperatures above 100 °C offer an interesting opportunity for heavy-duty applications. Especially for intermediate operating temperatures between 110 and 130 °C (IT-PEMFC), faster reaction kinetics, higher tolerance to fuel impurities, and water flooding as well as improved heat management of the fuel cell system have been observed. Perfluorosulfonic acid-based membranes (PFSAs) can be modified by incorporating additives or (nano)particle filler systems to improve their thermal and mechanical stability, proton conductivity, and long-term performance at these increased temperatures. Here, we investigate the effect of lithium fluoride particles embedded in PFSA membranes on their water retention behavior as well as on membrane durability in single-cell tests at elevated PEMFC operating temperatures of up to 120 °C. The lithium fluoride nanoparticle-modified membrane shows increased cell performance under both standard and intermediate temperature conditions. The observed performance boost can be explained by an increased mechanical stability at elevated temperatures of the membrane, due to stabilizing hydrophobic and hydrophilic domains, and an increased water uptake and storage capability, especially at low humidity levels during full cell operation. We propose that the nanoparticles adsorb water molecules by hydrogen bond formation, thus enhancing proton conductivity even at high temperatures resulting in these increased full cell performances of the LiF@PFSA-based composite membrane.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Polymer electrolyte membrane fuel cells (PEMFCs) operating at temperatures above 100 °C offer an interesting opportunity for heavy-duty applications. Especially for intermediate operating temperatures between 110 and 130 °C (IT-PEMFC), faster reaction kinetics, higher tolerance to fuel impurities, and water flooding as well as improved heat management of the fuel cell system have been observed. Perfluorosulfonic acid-based membranes (PFSAs) can be modified by incorporating additives or (nano)particle filler systems to improve their thermal and mechanical stability, proton conductivity, and long-term performance at these increased temperatures. Here, we investigate the effect of lithium fluoride particles embedded in PFSA membranes on their water retention behavior as well as on membrane durability in single-cell tests at elevated PEMFC operating temperatures of up to 120 °C. The lithium fluoride nanoparticle-modified membrane shows increased cell performance under both standard and intermediate temperature conditions. The observed performance boost can be explained by an increased mechanical stability at elevated temperatures of the membrane, due to stabilizing hydrophobic and hydrophilic domains, and an increased water uptake and storage capability, especially at low humidity levels during full cell operation. We propose that the nanoparticles adsorb water molecules by hydrogen bond formation, thus enhancing proton conductivity even at high temperatures resulting in these increased full cell performances of the LiF@PFSA-based composite membrane. |
2024 |
Giri, Amal Kanta; Oberhofer, Harald Large scale atomistic and quantum mechanical study of Na+ ion transport in liquid electrolytes for batteries Journal Article Journal of Molecular Liquids, 413 , pp. 125920, 2024, ISSN: 0167-7322. Abstract | Links | BibTeX | Tags: Battery materials, DFT, Electrolytes, MD simulation, Na ion, Sodium-ion batteries @article{Giri2024b, title = {Large scale atomistic and quantum mechanical study of Na+ ion transport in liquid electrolytes for batteries}, author = {Amal Kanta Giri and Harald Oberhofer}, url = {https://www.sciencedirect.com/science/article/pii/S0167732224019792}, doi = {https://doi.org/10.1016/j.molliq.2024.125920}, issn = {0167-7322}, year = {2024}, date = {2024-11-01}, journal = {Journal of Molecular Liquids}, volume = {413}, pages = {125920}, abstract = {Lithium–ion batteries (LIBs) have long dominated energy storage markets due to their high energy density and reliability. However, concerns over lithium scarcity and geographic distribution necessitate alternatives. Sodium-ion batteries (SIBs) offer a promising solution due to sodium's abundance, cost-effectiveness, and favorable electrochemical properties. This study investigates Na+ ion transport, aggregation, and performance in various organic electrolytes using molecular dynamics (MD) simulations and density functional theory (DFT) calculations. The electrolytes studied include ethylene carbonate (EC), propylene carbonate (PC), dimethoxyethane (DME), and dimethyl carbonate (DMC) at 320 K. We focused on conductivity, diffusivity, and survival probability of Na+ ions at different salt concentrations. Furthermore, the solvation structure and the binding energy of ions in the electrolytes are thoroughly analyzed. Key findings reveal that at 2 M salt concentration, Na+ ion diffusivity and ionic conductivity follow the order EC>PC>DME>DMC. Increasing salt concentration decreases self–diffusion coefficients of Na+ and PF6− ions across all electrolytes, affecting conductivity. EC shows the highest ionic conductivity at both 1 M and 2 M salt concentrations. These insights suggest that a 2 M NaPF6 concentration in EC optimizes ionic conductivity, making it ideal for high–performance SIBs. This study provides crucial understanding for optimizing electrolytes in SIBs, advancing their development for scalable energy storage solutions.}, keywords = {Battery materials, DFT, Electrolytes, MD simulation, Na ion, Sodium-ion batteries}, pubstate = {published}, tppubtype = {article} } Lithium–ion batteries (LIBs) have long dominated energy storage markets due to their high energy density and reliability. However, concerns over lithium scarcity and geographic distribution necessitate alternatives. Sodium-ion batteries (SIBs) offer a promising solution due to sodium's abundance, cost-effectiveness, and favorable electrochemical properties. This study investigates Na+ ion transport, aggregation, and performance in various organic electrolytes using molecular dynamics (MD) simulations and density functional theory (DFT) calculations. The electrolytes studied include ethylene carbonate (EC), propylene carbonate (PC), dimethoxyethane (DME), and dimethyl carbonate (DMC) at 320 K. We focused on conductivity, diffusivity, and survival probability of Na+ ions at different salt concentrations. Furthermore, the solvation structure and the binding energy of ions in the electrolytes are thoroughly analyzed. Key findings reveal that at 2 M salt concentration, Na+ ion diffusivity and ionic conductivity follow the order EC>PC>DME>DMC. Increasing salt concentration decreases self–diffusion coefficients of Na+ and PF6− ions across all electrolytes, affecting conductivity. EC shows the highest ionic conductivity at both 1 M and 2 M salt concentrations. These insights suggest that a 2 M NaPF6 concentration in EC optimizes ionic conductivity, making it ideal for high–performance SIBs. This study provides crucial understanding for optimizing electrolytes in SIBs, advancing their development for scalable energy storage solutions. |
Wenzel, Felix A; Stäter, Sebastian; O’Reilly, Padraic; Kreger, Klaus; Köhler, Jürgen; Hildner, Richard; Schmidt, Hans-Werner Isolated Hierarchical Superstructures with Highly Oriented P3HT Nanofibers Journal Article Macromolecules, 57 , pp. 10389 – 10398, 2024, ISSN: 1520-5835 . Abstract | Links | BibTeX | Tags: @article{Wenzel2024, title = {Isolated Hierarchical Superstructures with Highly Oriented P3HT Nanofibers}, author = {Felix A Wenzel and Sebastian Stäter and Padraic O’Reilly and Klaus Kreger and Jürgen Köhler and Richard Hildner and Hans-Werner Schmidt}, url = {https://doi.org/10.1021/acs.macromol.4c01618}, doi = {10.1021/acs.macromol.4c01618}, issn = {1520-5835 }, year = {2024}, date = {2024-10-30}, journal = {Macromolecules}, volume = {57}, pages = {10389 – 10398}, abstract = {The preparation of supramolecular mesoscale structures with high intrinsic order and orientation based on π-conjugated systems is of fundamental interest for studying their photophysical characteristics as well as for potential applications in (nano)photonics. However, the preparation, isolation and transfer of individual structures to substrates without compromising their structural integrity is challenging. Here we report on the controlled formation of hierarchical superstructures based on poly(3-hexylthiophene) (P3HT) comprising highly ordered and oriented P3HT nanofibers with lengths of up to 20 μm via a two-step self-assembly process. In the first step, we prepare defined supramolecular ribbons of N,N′-1,4-phenylenebis[4-pyridinecarboxamide]. In the second step, these ribbons act as efficient nucleation sites for the transcrystallization of P3HT into μm-long nanofibers from solution. The resulting shish-kebab-like superstructures can be purified and deposited on substrates without compromising their structural integrity. The densely packed and well-arranged P3HT nanofibers within the isolated superstructures feature a high orientational order parameter close to one up to a distance of 15 μm away from the initial nucleation sites. A systematic variation of photoluminescence spectra along the P3HT nanofibers in isolated superstructures indicates an increasing defect density toward the nanofiber end due to fractionation during growth. We anticipate that these findings can be transferred to designing and realizing superstructures as components for nanophotonic devices or light-harvesting antennae. year = 2024}, keywords = {}, pubstate = {published}, tppubtype = {article} } The preparation of supramolecular mesoscale structures with high intrinsic order and orientation based on π-conjugated systems is of fundamental interest for studying their photophysical characteristics as well as for potential applications in (nano)photonics. However, the preparation, isolation and transfer of individual structures to substrates without compromising their structural integrity is challenging. Here we report on the controlled formation of hierarchical superstructures based on poly(3-hexylthiophene) (P3HT) comprising highly ordered and oriented P3HT nanofibers with lengths of up to 20 μm via a two-step self-assembly process. In the first step, we prepare defined supramolecular ribbons of N,N′-1,4-phenylenebis[4-pyridinecarboxamide]. In the second step, these ribbons act as efficient nucleation sites for the transcrystallization of P3HT into μm-long nanofibers from solution. The resulting shish-kebab-like superstructures can be purified and deposited on substrates without compromising their structural integrity. The densely packed and well-arranged P3HT nanofibers within the isolated superstructures feature a high orientational order parameter close to one up to a distance of 15 μm away from the initial nucleation sites. A systematic variation of photoluminescence spectra along the P3HT nanofibers in isolated superstructures indicates an increasing defect density toward the nanofiber end due to fractionation during growth. We anticipate that these findings can be transferred to designing and realizing superstructures as components for nanophotonic devices or light-harvesting antennae. year = 2024 |
Lebeda, Timo; Aschebrock, Thilo; Kümmel, Stephan Balancing the Contributions to the Gradient Expansion: Accurate Binding and Band Gaps with a Nonempirical Meta-GGA Journal Article Phys. Rev. Lett., 133 , pp. 136402, 2024, ISSN: 1079-7114. @article{Lebeda2024, title = {Balancing the Contributions to the Gradient Expansion: Accurate Binding and Band Gaps with a Nonempirical Meta-GGA}, author = {Timo Lebeda and Thilo Aschebrock and Stephan Kümmel}, url = {https://link.aps.org/doi/10.1103/PhysRevLett.133.136402}, doi = {10.1103/PhysRevLett.133.136402}, issn = {1079-7114}, year = {2024}, date = {2024-09-01}, journal = {Phys. Rev. Lett.}, volume = {133}, pages = {136402}, publisher = {American Physical Society}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Yao, Yuxuan; Oberhofer, Harald Designing building blocks of covalent organic frameworks through on-the-fly batch-based Bayesian optimization Journal Article The Journal of Chemical Physics, 16 , pp. 074102 , 2024, ISSN: 0021-9606. Abstract | Links | BibTeX | Tags: @article{Yao2024b, title = {Designing building blocks of covalent organic frameworks through on-the-fly batch-based Bayesian optimization}, author = {Yuxuan Yao and Harald Oberhofer}, url = {https://doi.org/10.1063/5.0223540}, doi = {10.1063/5.0223540}, issn = {0021-9606}, year = {2024}, date = {2024-08-21}, journal = {The Journal of Chemical Physics}, volume = {16}, pages = {074102 }, abstract = {In this work, we use a Bayesian optimization (BO) algorithm to sample the space of covalent organic framework (COF) components aimed at the design of COFs with a high hole conductivity. COFs are crystalline, often porous coordination polymers, where organic molecular units—called building blocks (BBs)—are connected by covalent bonds. Even though we limit ourselves here to a space of three-fold symmetric BBs forming two-dimensional COF sheets, their design space is still much too large to be sampled by traditional means through evaluating the properties of each element in this space from first principles. In order to ensure valid BBs, we use a molecular generation algorithm that, by construction, leads to rigid three-fold symmetric molecules. The BO approach then trains two distinct surrogate models for two conductivity properties, level alignment vs a reference electrode and reorganization free energy, which are combined in a fitness function as the objective that evaluates BBs’ conductivities. These continuously improving surrogates allow the prediction of a material’s properties at a low computational cost. It thus allows us to select promising candidates which, together with candidates that are very different from the molecules already sampled, form the updated training sets of the surrogate models. In the course of 20 such training steps, we find a number of promising candidates, some being only variations on already known motifs and others being completely novel. Finally, we subject the six best such candidates to a computational reverse synthesis analysis to gauge their real-world synthesizability.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this work, we use a Bayesian optimization (BO) algorithm to sample the space of covalent organic framework (COF) components aimed at the design of COFs with a high hole conductivity. COFs are crystalline, often porous coordination polymers, where organic molecular units—called building blocks (BBs)—are connected by covalent bonds. Even though we limit ourselves here to a space of three-fold symmetric BBs forming two-dimensional COF sheets, their design space is still much too large to be sampled by traditional means through evaluating the properties of each element in this space from first principles. In order to ensure valid BBs, we use a molecular generation algorithm that, by construction, leads to rigid three-fold symmetric molecules. The BO approach then trains two distinct surrogate models for two conductivity properties, level alignment vs a reference electrode and reorganization free energy, which are combined in a fitness function as the objective that evaluates BBs’ conductivities. These continuously improving surrogates allow the prediction of a material’s properties at a low computational cost. It thus allows us to select promising candidates which, together with candidates that are very different from the molecules already sampled, form the updated training sets of the surrogate models. In the course of 20 such training steps, we find a number of promising candidates, some being only variations on already known motifs and others being completely novel. Finally, we subject the six best such candidates to a computational reverse synthesis analysis to gauge their real-world synthesizability. |
Zhang, Heyou; Dharpure, Pankaj; Philipp, Michael; Mulvaney, Paul; Thelakkat, Mukundan; Köhler, Jürgen Purely Optical, Reversible, Read-Write-Erase Cycling Using Photoswitchable Beads in Micropatterned Arrays Journal Article Advanced Optical Materials, 12 (26), pp. 2401029, 2024, ISSN: 2195-1071. Abstract | Links | BibTeX | Tags: micro patterned arrays, photo switchable polymer beads, photochromism, photonic logic gates @article{Zhang2024d, title = {Purely Optical, Reversible, Read-Write-Erase Cycling Using Photoswitchable Beads in Micropatterned Arrays}, author = {Heyou Zhang and Pankaj Dharpure and Michael Philipp and Paul Mulvaney and Mukundan Thelakkat and Jürgen Köhler}, url = {https://advanced.onlinelibrary.wiley.com/doi/abs/10.1002/adom.202401029}, doi = {https://doi.org/10.1002/adom.202401029}, issn = {2195-1071}, year = {2024}, date = {2024-07-16}, journal = {Advanced Optical Materials}, volume = {12}, number = {26}, pages = {2401029}, abstract = {Abstract Using surface-templated electrophoretic deposition, arrays of polymer beads (photonic units) incorporating photo-switchable DAE molecules are created, which can be reversibly and individually switched between high and low emission states by direct photo-excitation, without any energy or electron transfer processes within the molecular system. The micropatterned array of these photonic units is spectroscopically characterized in detail and optimized with respect to both signal contrast and cross-talk. The optimum optical parameters including laser intensity, wavelength and duration of irradiation are elucidated and ideal conditions for creating reversible on/off cycles in a micropatterned array are determined. 500 such cycles are demonstrated with no obvious on/off contrast attenuation. The ability to process binary information is demonstrated by selectively writing information to the given photonic unit, reading the resultant emissive signal pattern and finally erasing the information again, which in turn demonstrates the possibility of continuous recording. This basic study paves the way for building complex circuits using spatially well-arranged photonic units.}, keywords = {micro patterned arrays, photo switchable polymer beads, photochromism, photonic logic gates}, pubstate = {published}, tppubtype = {article} } Abstract Using surface-templated electrophoretic deposition, arrays of polymer beads (photonic units) incorporating photo-switchable DAE molecules are created, which can be reversibly and individually switched between high and low emission states by direct photo-excitation, without any energy or electron transfer processes within the molecular system. The micropatterned array of these photonic units is spectroscopically characterized in detail and optimized with respect to both signal contrast and cross-talk. The optimum optical parameters including laser intensity, wavelength and duration of irradiation are elucidated and ideal conditions for creating reversible on/off cycles in a micropatterned array are determined. 500 such cycles are demonstrated with no obvious on/off contrast attenuation. The ability to process binary information is demonstrated by selectively writing information to the given photonic unit, reading the resultant emissive signal pattern and finally erasing the information again, which in turn demonstrates the possibility of continuous recording. This basic study paves the way for building complex circuits using spatially well-arranged photonic units. |
Schröder, Dennis; Kreger, Klaus; Mansfeld, Ulrich; Schmidt, Hans-Werner Controlled Surface Decoration with Functional Supramolecular Nanofibers by Physical Vapor Deposition Journal Article Advanced Materials Interfaces, 11 (25), pp. 2400259, 2024, ISSN: 2196-7350. Abstract | Links | BibTeX | Tags: 1, 3, 5-benzenetricaboxamides, gold nanoparticles, heterogenous catalysis, supramolecular nanofibers, surface decoration @article{Schröder2024, title = {Controlled Surface Decoration with Functional Supramolecular Nanofibers by Physical Vapor Deposition}, author = {Dennis Schröder and Klaus Kreger and Ulrich Mansfeld and Hans-Werner Schmidt}, url = {https://advanced.onlinelibrary.wiley.com/doi/abs/10.1002/admi.202400259}, doi = {https://doi.org/10.1002/admi.202400259}, issn = {2196-7350}, year = {2024}, date = {2024-06-27}, journal = {Advanced Materials Interfaces}, volume = {11}, number = {25}, pages = {2400259}, abstract = {Abstract Surface decoration of support structures by physical vapor deposition (PVD) of small molecular building blocks offers a versatile platform to realize functional supramolecular nanofibers in a controlled manner and with tailored properties. Here, details on the preparation of surface-decorated polyamide fabrics by PVD using N1,N3,N5-tris[2-(diisopropylamino)-ethyl]-1,3,5-benzenetricarboxamide (1) as a molecular building block are reported. It is shown that a defined morphology with uniform nanofiber length can be achieved, which is controlled by the PVD conditions. The functional periphery of supramolecular nanofibers of 1 allows the immobilization of gold nanoparticles (AuNPs). This results in AuNP-loaded nanostructures with a high surface area, which can be used as a heterogenous catalyst for the reduction of 4-nitrophenol in aqueous media. The surface-decorated support structures with firmly deposited AuNPs also provide the opportunity to conveniently reuse these structures without compromising the catalytic performance. This approach provides fabrication strategies for the controlled surface decoration of macroscopic support structures with small molecular building blocks by PVD with the potential to realize functional robust supramolecular nanofibers for various catalytic or filtration applications.}, keywords = {1, 3, 5-benzenetricaboxamides, gold nanoparticles, heterogenous catalysis, supramolecular nanofibers, surface decoration}, pubstate = {published}, tppubtype = {article} } Abstract Surface decoration of support structures by physical vapor deposition (PVD) of small molecular building blocks offers a versatile platform to realize functional supramolecular nanofibers in a controlled manner and with tailored properties. Here, details on the preparation of surface-decorated polyamide fabrics by PVD using N1,N3,N5-tris[2-(diisopropylamino)-ethyl]-1,3,5-benzenetricarboxamide (1) as a molecular building block are reported. It is shown that a defined morphology with uniform nanofiber length can be achieved, which is controlled by the PVD conditions. The functional periphery of supramolecular nanofibers of 1 allows the immobilization of gold nanoparticles (AuNPs). This results in AuNP-loaded nanostructures with a high surface area, which can be used as a heterogenous catalyst for the reduction of 4-nitrophenol in aqueous media. The surface-decorated support structures with firmly deposited AuNPs also provide the opportunity to conveniently reuse these structures without compromising the catalytic performance. This approach provides fabrication strategies for the controlled surface decoration of macroscopic support structures with small molecular building blocks by PVD with the potential to realize functional robust supramolecular nanofibers for various catalytic or filtration applications. |
Brütting, Moritz; Bahmann, Hilke; Kümmel, Stephan Predicting fundamental gaps accurately from density functional theory with non-empirical local range separation Journal Article The Journal of Chemical Physics, 160 (18), pp. 181101, 2024, ISSN: 0021-9606. Abstract | Links | BibTeX | Tags: @article{Brütting2024, title = {Predicting fundamental gaps accurately from density functional theory with non-empirical local range separation}, author = {Moritz Brütting and Hilke Bahmann and Stephan Kümmel}, url = {https://doi.org/10.1063/5.0204379}, doi = {10.1063/5.0204379}, issn = {0021-9606}, year = {2024}, date = {2024-05-14}, journal = {The Journal of Chemical Physics}, volume = {160}, number = {18}, pages = {181101}, abstract = {We present an exchange–correlation approximation in which the Coulomb interaction is split into long- and short-range components and the range separation is determined by a non-empirical density functional. The functional respects important constraints, such as the homogeneous and slowly varying density limits, leads to the correct long-range potential, and eliminates one-electron self-interaction. Our approach is designed for spectroscopic purposes and closely approximates the piecewise linearity of the energy as a function of the particle number. The functional’s accuracy for predicting the fundamental gap in generalized Kohn–Sham theory is demonstrated for a large number of systems, including organic semiconductors with a notoriously difficult electronic structure.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We present an exchange–correlation approximation in which the Coulomb interaction is split into long- and short-range components and the range separation is determined by a non-empirical density functional. The functional respects important constraints, such as the homogeneous and slowly varying density limits, leads to the correct long-range potential, and eliminates one-electron self-interaction. Our approach is designed for spectroscopic purposes and closely approximates the piecewise linearity of the energy as a function of the particle number. The functional’s accuracy for predicting the fundamental gap in generalized Kohn–Sham theory is demonstrated for a large number of systems, including organic semiconductors with a notoriously difficult electronic structure. |
Carta, Alberto; Wittmann, Bernd; Kreger, Klaus; Schmidt, Hans-Werner; Jansen, Thomas L C; Hildner, Richard Spatial Correlations Drive Long-Range Transport and Trapping of Excitons in Single H-Aggregates: Experiment and Theory Journal Article The Journal of Physical Chemistry Letters, 15 (10), pp. 2697-2707, 2024, ISSN: 1948-7185, (PMID: 38427597). Abstract | Links | BibTeX | Tags: @article{Carta2024, title = {Spatial Correlations Drive Long-Range Transport and Trapping of Excitons in Single H-Aggregates: Experiment and Theory}, author = {Alberto Carta and Bernd Wittmann and Klaus Kreger and Hans-Werner Schmidt and Thomas L C Jansen and Richard Hildner}, url = {https://doi.org/10.1021/acs.jpclett.3c03586}, doi = {10.1021/acs.jpclett.3c03586}, issn = {1948-7185}, year = {2024}, date = {2024-03-01}, journal = {The Journal of Physical Chemistry Letters}, volume = {15}, number = {10}, pages = {2697-2707}, abstract = {Describing long-range energy transport is a crucial step, both toward deepening our knowledge on natural light-harvesting systems and toward developing novel photoactive materials. Here, we combine experiment and theory to resolve and reproduce energy transport on pico- to nanosecond time scales in single H-type supramolecular nanofibers based on carbonyl-bridged triarylamines (CBT). Each nanofiber shows energy transport dynamics over long distances up to ∼1 μm, despite exciton trapping at specific positions along the nanofibers. Using a minimal Frenkel exciton model including disorder, we demonstrate that spatial correlations in the normally distributed site energies are crucial to reproduce the experimental data. In particular, we can observe the long-range and subdiffusive nature of the exciton dynamics as well as the trapping behavior of excitons in specific locations of the nanofiber. This trapping behavior introduces a net directionality or asymmetry in the exciton dynamics as observed experimentally. year = 2024}, note = {PMID: 38427597}, keywords = {}, pubstate = {published}, tppubtype = {article} } Describing long-range energy transport is a crucial step, both toward deepening our knowledge on natural light-harvesting systems and toward developing novel photoactive materials. Here, we combine experiment and theory to resolve and reproduce energy transport on pico- to nanosecond time scales in single H-type supramolecular nanofibers based on carbonyl-bridged triarylamines (CBT). Each nanofiber shows energy transport dynamics over long distances up to ∼1 μm, despite exciton trapping at specific positions along the nanofibers. Using a minimal Frenkel exciton model including disorder, we demonstrate that spatial correlations in the normally distributed site energies are crucial to reproduce the experimental data. In particular, we can observe the long-range and subdiffusive nature of the exciton dynamics as well as the trapping behavior of excitons in specific locations of the nanofiber. This trapping behavior introduces a net directionality or asymmetry in the exciton dynamics as observed experimentally. year = 2024 |
Shen, Guibin; Li, Xin; Zou, Yuqin; Dong, Hongye; Zhu, Dongping; Jiang, Yanglin; Ng, Xin Ren; Lin, Fen; Müller-Buschbaum, Peter; Mu, Cheng High-Performance and Large-Area Inverted Perovskite Solar Cells Based on NiOx Films Enabled with A Novel Microstructure-Control Technology Journal Article Energy and Environmental Materials, 7 (1), 2024, ISSN: 25750348, (Cited by: 2; All Open Access, Hybrid Gold Open Access). Abstract | Links | BibTeX | Tags: @article{Shen2024, title = {High-Performance and Large-Area Inverted Perovskite Solar Cells Based on NiOx Films Enabled with A Novel Microstructure-Control Technology}, author = {Guibin Shen and Xin Li and Yuqin Zou and Hongye Dong and Dongping Zhu and Yanglin Jiang and Xin Ren Ng and Fen Lin and Peter Müller-Buschbaum and Cheng Mu}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85146311402&doi=10.1002%2feem2.12504&partnerID=40&md5=898f1a69605b2ff9be18105958ee4a77}, doi = {10.1002/eem2.12504}, issn = {25750348}, year = {2024}, date = {2024-01-01}, journal = {Energy and Environmental Materials}, volume = {7}, number = {1}, publisher = {John Wiley and Sons Inc}, abstract = {The improvement in the efficiency of inverted perovskite solar cells (PSCs) is significantly limited by undesirable contact at the NiOX/perovskite interface. In this study, a novel microstructure-control technology is proposed for fabrication of porous NiOX films using Pluronic P123 as the structure-directing agent and acetylacetone (AcAc) as the coordination agent. The synthesized porous NiOX films enhanced the hole extraction efficiency and reduced recombination defects at the NiOX/perovskite interface. Consequently, without any modification, the power conversion efficiency (PCE) of the PSC with MAPbI3 as the absorber layer improved from 16.50% to 19.08%. Moreover, the PCE of the device composed of perovskite Cs0.05(MA0.15FA0.85)0.95Pb(I0.85Br0.15)3 improved from 17.49% to 21.42%. Furthermore, the application of the fabricated porous NiOX on fluorine-doped tin oxide (FTO) substrates enabled the fabrication of large-area PSCs (1.2 cm2) with a PCE of 19.63%. This study provides a novel strategy for improving the contact at the NiOX/perovskite interface for the fabrication of high-performance large-area perovskite solar cells. © 2022 The Authors. Energy & Environmental Materials published by John Wiley & Sons Australia, Ltd on behalf of Zhengzhou University.}, note = {Cited by: 2; All Open Access, Hybrid Gold Open Access}, keywords = {}, pubstate = {published}, tppubtype = {article} } The improvement in the efficiency of inverted perovskite solar cells (PSCs) is significantly limited by undesirable contact at the NiOX/perovskite interface. In this study, a novel microstructure-control technology is proposed for fabrication of porous NiOX films using Pluronic P123 as the structure-directing agent and acetylacetone (AcAc) as the coordination agent. The synthesized porous NiOX films enhanced the hole extraction efficiency and reduced recombination defects at the NiOX/perovskite interface. Consequently, without any modification, the power conversion efficiency (PCE) of the PSC with MAPbI3 as the absorber layer improved from 16.50% to 19.08%. Moreover, the PCE of the device composed of perovskite Cs0.05(MA0.15FA0.85)0.95Pb(I0.85Br0.15)3 improved from 17.49% to 21.42%. Furthermore, the application of the fabricated porous NiOX on fluorine-doped tin oxide (FTO) substrates enabled the fabrication of large-area PSCs (1.2 cm2) with a PCE of 19.63%. This study provides a novel strategy for improving the contact at the NiOX/perovskite interface for the fabrication of high-performance large-area perovskite solar cells. © 2022 The Authors. Energy & Environmental Materials published by John Wiley & Sons Australia, Ltd on behalf of Zhengzhou University. |
Zou, Yuqin; Song, Qili; Zhou, Jungui; Yin, Shanshan; Li, Yanan; Apfelbeck, Fabian A C; Zheng, Tianle; Fung, Man-Keung; Mu, Cheng; Müller-Buschbaum, Peter Ammonium Sulfate to Modulate Crystallization for High-Performance Rigid and Flexible Perovskite Solar Cells Journal Article Small, 2024, ISSN: 16136810, (Cited by: 0). Abstract | Links | BibTeX | Tags: @article{Zou2024c, title = {Ammonium Sulfate to Modulate Crystallization for High-Performance Rigid and Flexible Perovskite Solar Cells}, author = {Yuqin Zou and Qili Song and Jungui Zhou and Shanshan Yin and Yanan Li and Fabian A C Apfelbeck and Tianle Zheng and Man-Keung Fung and Cheng Mu and Peter Müller-Buschbaum}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85191834414&doi=10.1002%2fsmll.202401456&partnerID=40&md5=f3bb1a2131cb975eaa85d793053bbed2}, doi = {10.1002/smll.202401456}, issn = {16136810}, year = {2024}, date = {2024-01-01}, journal = {Small}, publisher = {John Wiley and Sons Inc}, abstract = {Perovskite solar cells (PSCs) are attracting widespread research and attention as highly promising candidates in the field of electronic photovoltaics owing to their exceptional power conversion efficiency (PCE). However, rigid or flexible PSCs still face challenges in preparing full-coverage and low-defect perovskite films, as well as achieving highly reproducible and highly stable devices. Herein, a multifunctional additive 2-aminoethyl hydrogen sulfate (AES) is designed to regulate the film crystallization and thereby form flat and pinhole-free perovskite films. It is found that the introduction of AES can effectively passivate defects, restrain charge carrier recombination, and then achieve a higher fill factor. As seen with grazing incidence wide-angle X-ray scattering (GIWAXS), this approach does not affect the crystal orientation distribution. It is observed that AES addition shows a universality across different perovskite components since the PCE is improved up to 20.7% for FA0.97MA0.03Pb(I0.97Br0.03)3-AES, 22.85% for Cs0.05FA0.95PbI3-AES, 22.23% for FAPbI2.7Br0.3-AES, and 23.32% for FAPI-AES rigid devices. Remarkably, the non-encapsulated flexible Cs0.05 (FA0.85MA0.15)0.95Pb(I0.85Br0.15)3 device with AES additive delivers a PCE of 20.1% and maintains over 97% of its initial efficiency under ambient conditions (25 ± 5% relative humidity) over 2280 h of aging. © 2024 The Authors. Small published by Wiley-VCH GmbH.}, note = {Cited by: 0}, keywords = {}, pubstate = {published}, tppubtype = {article} } Perovskite solar cells (PSCs) are attracting widespread research and attention as highly promising candidates in the field of electronic photovoltaics owing to their exceptional power conversion efficiency (PCE). However, rigid or flexible PSCs still face challenges in preparing full-coverage and low-defect perovskite films, as well as achieving highly reproducible and highly stable devices. Herein, a multifunctional additive 2-aminoethyl hydrogen sulfate (AES) is designed to regulate the film crystallization and thereby form flat and pinhole-free perovskite films. It is found that the introduction of AES can effectively passivate defects, restrain charge carrier recombination, and then achieve a higher fill factor. As seen with grazing incidence wide-angle X-ray scattering (GIWAXS), this approach does not affect the crystal orientation distribution. It is observed that AES addition shows a universality across different perovskite components since the PCE is improved up to 20.7% for FA0.97MA0.03Pb(I0.97Br0.03)3-AES, 22.85% for Cs0.05FA0.95PbI3-AES, 22.23% for FAPbI2.7Br0.3-AES, and 23.32% for FAPI-AES rigid devices. Remarkably, the non-encapsulated flexible Cs0.05 (FA0.85MA0.15)0.95Pb(I0.85Br0.15)3 device with AES additive delivers a PCE of 20.1% and maintains over 97% of its initial efficiency under ambient conditions (25 ± 5% relative humidity) over 2280 h of aging. © 2024 The Authors. Small published by Wiley-VCH GmbH. |
Kang, Ziyong; Wang, Kun; Zhang, Lu; Yang, Yang; Wu, Jiandong; Tong, Yu; Yan, Peng; Chen, Yali; Qi, Heng; Sun, Kun; Müller-Buschbaum, Peter; Zhang, Xuewen; Shang, Jingzhi; Wang, Hongqiang Homogenizing The Low-Dimensional Phases for Stable 2D-3D Tin Perovskite Solar Cells Journal Article Small, 2024, ISSN: 16136810, (Cited by: 0). Abstract | Links | BibTeX | Tags: @article{Kang2024c, title = {Homogenizing The Low-Dimensional Phases for Stable 2D-3D Tin Perovskite Solar Cells}, author = {Ziyong Kang and Kun Wang and Lu Zhang and Yang Yang and Jiandong Wu and Yu Tong and Peng Yan and Yali Chen and Heng Qi and Kun Sun and Peter Müller-Buschbaum and Xuewen Zhang and Jingzhi Shang and Hongqiang Wang}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85197519682&doi=10.1002%2fsmll.202402028&partnerID=40&md5=596cfebd32154af1fbc81a021fabdbc5}, doi = {10.1002/smll.202402028}, issn = {16136810}, year = {2024}, date = {2024-01-01}, journal = {Small}, publisher = {John Wiley and Sons Inc}, abstract = {2D-3D tin-based perovskites are considered as promising candidates for achieving efficient lead-free perovskite solar cells (PSCs). However, the existence of multiple low-dimensional phases formed during the film preparation hinders the efficient transport of charge carriers. In addition, the non-homogeneous distribution of low-dimensional phases leads to lattice distortion and increases the defect density, which are undesirable for the stability of tin-based PSCs. Here, mixed spacer cations [diethylamine (DEA+) and phenethylamine (PEA+)] are introduced into tin perovskite films to modulate the distribution of the 2D phases. It is found that compared to the film with only PEA+, the combination of DEA+ and PEA+ favors the formation of homogeneous low-dimensional perovskite phases with three octahedral monolayers (n = 3), especially near the bottom interface between perovskite and hole transport layer. The homogenization of 2D phases help improve the film quality with reduced lattice distortion and released strain. With these merits, the tin PSC shows significantly improved stability with 94% of its initial efficiency retained after storing in a nitrogen atmosphere for over 4600 h, and over 80% efficiency maintained after continuous illumination for 400 h. © 2024 Wiley-VCH GmbH.}, note = {Cited by: 0}, keywords = {}, pubstate = {published}, tppubtype = {article} } 2D-3D tin-based perovskites are considered as promising candidates for achieving efficient lead-free perovskite solar cells (PSCs). However, the existence of multiple low-dimensional phases formed during the film preparation hinders the efficient transport of charge carriers. In addition, the non-homogeneous distribution of low-dimensional phases leads to lattice distortion and increases the defect density, which are undesirable for the stability of tin-based PSCs. Here, mixed spacer cations [diethylamine (DEA+) and phenethylamine (PEA+)] are introduced into tin perovskite films to modulate the distribution of the 2D phases. It is found that compared to the film with only PEA+, the combination of DEA+ and PEA+ favors the formation of homogeneous low-dimensional perovskite phases with three octahedral monolayers (n = 3), especially near the bottom interface between perovskite and hole transport layer. The homogenization of 2D phases help improve the film quality with reduced lattice distortion and released strain. With these merits, the tin PSC shows significantly improved stability with 94% of its initial efficiency retained after storing in a nitrogen atmosphere for over 4600 h, and over 80% efficiency maintained after continuous illumination for 400 h. © 2024 Wiley-VCH GmbH. |
Arslanova, Ksenija; Ganswindt, Patrick; Lorenzen, Tizian; Kostyurina, Ekaterina; Karaghiosoff, Konstantin; Nickel, Bert; Müller-Caspary, Knut; Urban, Alexander S Synthesis of Cs3Cu2I5 Nanocrystals in a Continuous Flow System Journal Article Small, 2024, ISSN: 16136810, (Cited by: 0; All Open Access, Hybrid Gold Open Access). Abstract | Links | BibTeX | Tags: @article{Arslanova2024, title = {Synthesis of Cs3Cu2I5 Nanocrystals in a Continuous Flow System}, author = {Ksenija Arslanova and Patrick Ganswindt and Tizian Lorenzen and Ekaterina Kostyurina and Konstantin Karaghiosoff and Bert Nickel and Knut Müller-Caspary and Alexander S Urban}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85198390458&doi=10.1002%2fsmll.202403572&partnerID=40&md5=00d5643d09a0ac08b39bce2f64dec47c}, doi = {10.1002/smll.202403572}, issn = {16136810}, year = {2024}, date = {2024-01-01}, journal = {Small}, publisher = {John Wiley and Sons Inc}, abstract = {Achieving the goal of generating all of the world's energy via renewable sources and significantly reducing the energy usage will require the development of novel, abundant, nontoxic energy conversion materials. Here, a cost-efficient and scalable continuous flow synthesis of Cs3Cu2I5 nanocrystals is developed as a basis for the rapid advancement of novel nanomaterials. Ideal precursor solutions are obtained through a novel batch synthesis, whose product served as a benchmark for the subsequent flow synthesis. Realizing this setup enabled a reproducible fabrication of Cs3Cu2I5 nanocrystals. The effect of volumetric flow rate and temperature on the final product's morphology and optical properties are determined, obtaining 21% quantum yield with the optimal configuration. Consequently, the size and morphology of the nanocrystals can be tuned with far more precision and in a much broader range than previously achievable. The flow setup is readily applicable to other relevant nanomaterials. It should enable a rapid determination of a material's potential and subsequently optimize its desired properties for renewable energy generation or efficient optoelectronics. © 2024 The Author(s). Small published by Wiley-VCH GmbH.}, note = {Cited by: 0; All Open Access, Hybrid Gold Open Access}, keywords = {}, pubstate = {published}, tppubtype = {article} } Achieving the goal of generating all of the world's energy via renewable sources and significantly reducing the energy usage will require the development of novel, abundant, nontoxic energy conversion materials. Here, a cost-efficient and scalable continuous flow synthesis of Cs3Cu2I5 nanocrystals is developed as a basis for the rapid advancement of novel nanomaterials. Ideal precursor solutions are obtained through a novel batch synthesis, whose product served as a benchmark for the subsequent flow synthesis. Realizing this setup enabled a reproducible fabrication of Cs3Cu2I5 nanocrystals. The effect of volumetric flow rate and temperature on the final product's morphology and optical properties are determined, obtaining 21% quantum yield with the optimal configuration. Consequently, the size and morphology of the nanocrystals can be tuned with far more precision and in a much broader range than previously achievable. The flow setup is readily applicable to other relevant nanomaterials. It should enable a rapid determination of a material's potential and subsequently optimize its desired properties for renewable energy generation or efficient optoelectronics. © 2024 The Author(s). Small published by Wiley-VCH GmbH. |
Zhang, Kaicheng; Liu, Chao; Peng, Zijian; Li, Chaohui; Tian, Jingjing; Li, Canru; Cerrillo, José Garcia; Dong, Lirong; Streller, Fabian; Späth, Andreas; Musiienko, Artem; Englhard, Jonas; Li, Ning; Zhang, Jiyun; Du, Tian; Sathasivam, Sanjayan; Macdonald, Thomas J; These, Albert; Corre, Vincent Le M; Forberich, Karen; Meng, Wei; Fink, Rainer H; Osvet, Andres; Lüer, Larry; Bachmann, Julien; Tong, Jinhui; Brabec, Christoph J Binary cations minimize energy loss in the wide-band-gap perovskite toward efficient all-perovskite tandem solar cells Journal Article Joule, 2024, ISSN: 25424351, (Cited by: 0). Abstract | Links | BibTeX | Tags: @article{Zhang2024c, title = {Binary cations minimize energy loss in the wide-band-gap perovskite toward efficient all-perovskite tandem solar cells}, author = {Kaicheng Zhang and Chao Liu and Zijian Peng and Chaohui Li and Jingjing Tian and Canru Li and José Garcia Cerrillo and Lirong Dong and Fabian Streller and Andreas Späth and Artem Musiienko and Jonas Englhard and Ning Li and Jiyun Zhang and Tian Du and Sanjayan Sathasivam and Thomas J Macdonald and Albert These and Vincent M Le Corre and Karen Forberich and Wei Meng and Rainer H Fink and Andres Osvet and Larry Lüer and Julien Bachmann and Jinhui Tong and Christoph J Brabec}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85201705955&doi=10.1016%2fj.joule.2024.07.003&partnerID=40&md5=4f7fd2d1af7276ca125d440e37938fe5}, doi = {10.1016/j.joule.2024.07.003}, issn = {25424351}, year = {2024}, date = {2024-01-01}, journal = {Joule}, publisher = {Cell Press}, abstract = {Perovskite-based tandem solar cells stand at the forefront of photovoltaic innovation due to their exceptional performance and cost-effective fabrication. This study focuses on minimizing energy losses within a 1.80 eV perovskite sub-cell. We demonstrate that the surface treatment of perovskite with binary guanidinium bromide and 4-fluorophenylammonium iodide synergistically reduces defect densities and adjusts interfacial energy-level alignment. The enhanced passivation effect and the formation of a surface dipole significantly reduce nonradiative recombination and transport losses, leading to a notable increase in the open-circuit voltage and fill factor product, thereby achieving an impressive power conversion efficiency (PCE) of 19.0%. The reproducibility of these findings is confirmed by consistent results across different laboratories. Furthermore, integration with a narrow-band-gap perovskite yields an all-perovskite tandem device with a PCE of 27.2%. This comprehensive understanding of the pivotal role of spacer cations in surface treatment significantly advances the pathway toward efficient perovskite photovoltaics. © 2024 Elsevier Inc.}, note = {Cited by: 0}, keywords = {}, pubstate = {published}, tppubtype = {article} } Perovskite-based tandem solar cells stand at the forefront of photovoltaic innovation due to their exceptional performance and cost-effective fabrication. This study focuses on minimizing energy losses within a 1.80 eV perovskite sub-cell. We demonstrate that the surface treatment of perovskite with binary guanidinium bromide and 4-fluorophenylammonium iodide synergistically reduces defect densities and adjusts interfacial energy-level alignment. The enhanced passivation effect and the formation of a surface dipole significantly reduce nonradiative recombination and transport losses, leading to a notable increase in the open-circuit voltage and fill factor product, thereby achieving an impressive power conversion efficiency (PCE) of 19.0%. The reproducibility of these findings is confirmed by consistent results across different laboratories. Furthermore, integration with a narrow-band-gap perovskite yields an all-perovskite tandem device with a PCE of 27.2%. This comprehensive understanding of the pivotal role of spacer cations in surface treatment significantly advances the pathway toward efficient perovskite photovoltaics. © 2024 Elsevier Inc. |
Aigner, Andreas; Weber, Thomas; Wester, Alwin; Maier, Stefan A; Tittl, Andreas Continuous spectral and coupling-strength encoding with dual-gradient metasurfaces Journal Article Nature Nanotechnology, 2024, ISSN: 17483387, (Cited by: 0; All Open Access, Hybrid Gold Open Access). Abstract | Links | BibTeX | Tags: Molecular recognition; Photocatalysis; Coupling strengths; Encodings; Light-matter interactions; Metasurface; Nano scale; Parameter spaces; Quality factors; Spectral feature; Spectral overlap; Two parameter; absorption; article; pharmaceutics; photocatalysis; photon; solid state; Chemical sensors @article{Aigner2024b, title = {Continuous spectral and coupling-strength encoding with dual-gradient metasurfaces}, author = {Andreas Aigner and Thomas Weber and Alwin Wester and Stefan A Maier and Andreas Tittl}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85202055547&doi=10.1038%2fs41565-024-01767-2&partnerID=40&md5=42bcf5a02280697e22de3f6008310232}, doi = {10.1038/s41565-024-01767-2}, issn = {17483387}, year = {2024}, date = {2024-01-01}, journal = {Nature Nanotechnology}, publisher = {Nature Research}, abstract = {To control and enhance light–matter interactions at the nanoscale, two parameters are central: the spectral overlap between an optical cavity mode and the material’s spectral features (for example, excitonic or molecular absorption lines), and the quality factor of the cavity. Controlling both parameters simultaneously would enable the investigation of systems with complex spectral features, such as multicomponent molecular mixtures or heterogeneous solid-state materials. So far, it has been possible only to sample a limited set of data points within this two-dimensional parameter space. Here we introduce a nanophotonic approach that can simultaneously and continuously encode the spectral and quality-factor parameter space within a compact spatial area. We use a dual-gradient metasurface design composed of a two-dimensional array of smoothly varying subwavelength nanoresonators, each supporting a unique mode based on symmetry-protected bound states in the continuum. This results in 27,500 distinct modes and a mode density approaching the theoretical upper limit for metasurfaces. By applying our platform to surface-enhanced molecular spectroscopy, we find that the optimal quality factor for maximum sensitivity depends on the amount of analyte, enabling effective molecular detection regardless of analyte concentration within a single dual-gradient metasurface. Our design provides a method to analyse the complete spectral and coupling-strength parameter space of complex material systems for applications such as photocatalysis, chemical sensing and entangled photon generation. © The Author(s) 2024.}, note = {Cited by: 0; All Open Access, Hybrid Gold Open Access}, keywords = {Molecular recognition; Photocatalysis; Coupling strengths; Encodings; Light-matter interactions; Metasurface; Nano scale; Parameter spaces; Quality factors; Spectral feature; Spectral overlap; Two parameter; absorption; article; pharmaceutics; photocatalysis; photon; solid state; Chemical sensors}, pubstate = {published}, tppubtype = {article} } To control and enhance light–matter interactions at the nanoscale, two parameters are central: the spectral overlap between an optical cavity mode and the material’s spectral features (for example, excitonic or molecular absorption lines), and the quality factor of the cavity. Controlling both parameters simultaneously would enable the investigation of systems with complex spectral features, such as multicomponent molecular mixtures or heterogeneous solid-state materials. So far, it has been possible only to sample a limited set of data points within this two-dimensional parameter space. Here we introduce a nanophotonic approach that can simultaneously and continuously encode the spectral and quality-factor parameter space within a compact spatial area. We use a dual-gradient metasurface design composed of a two-dimensional array of smoothly varying subwavelength nanoresonators, each supporting a unique mode based on symmetry-protected bound states in the continuum. This results in 27,500 distinct modes and a mode density approaching the theoretical upper limit for metasurfaces. By applying our platform to surface-enhanced molecular spectroscopy, we find that the optimal quality factor for maximum sensitivity depends on the amount of analyte, enabling effective molecular detection regardless of analyte concentration within a single dual-gradient metasurface. Our design provides a method to analyse the complete spectral and coupling-strength parameter space of complex material systems for applications such as photocatalysis, chemical sensing and entangled photon generation. © The Author(s) 2024. |
Hungenberg, Julian; Hochgesang, Adrian; Meichsner, Florian; Thelakkat, Mukundan Self-Doped Mixed Ionic-Electronic Conductors to Tune the Threshold Voltage and the Mode of Operation in Organic Electrochemical Transistors Journal Article Advanced Functional Materials, 2024, ISSN: 1616301X, (Cited by: 0; All Open Access, Hybrid Gold Open Access). Abstract | Links | BibTeX | Tags: @article{Hungenberg2024, title = {Self-Doped Mixed Ionic-Electronic Conductors to Tune the Threshold Voltage and the Mode of Operation in Organic Electrochemical Transistors}, author = {Julian Hungenberg and Adrian Hochgesang and Florian Meichsner and Mukundan Thelakkat}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85199366751&doi=10.1002%2fadfm.202407067&partnerID=40&md5=e507f7fe2d70666e3bcced9838e54c3b}, doi = {10.1002/adfm.202407067}, issn = {1616301X}, year = {2024}, date = {2024-01-01}, journal = {Advanced Functional Materials}, publisher = {John Wiley and Sons Inc}, abstract = {Organic mixed ionic-electronic conductors with tunable doping, low threshold voltages, and air stability are crucial for bioelectronic applications. A homopolymer based on an alkoxy thiophene monomer and its copolymer with a thiophene carrying ethylene glycol side chains are synthesized and converted to self-doped conjugated polyelectrolytes, P3HOTS-TMA+, and P3HOTS-TMA+-co-P3MEEET. The self-doping occurs during the conversion to polyelectrolytes. Both polyelectrolytes show high electrical conductivity without any external dopants. UV–Vis–NIR spectroscopy and spectroelectrochemistry confirm excellent air stability of the doped state. In an organic electrochemical transistor (OECT), the P3HOTS-TMA+ operates in depletion mode, while P3HOTS-TMA+-co-P3MEEET exhibits accumulation mode of operation with low threshold voltage, both showing fast response times. On the other hand, the non-doped homopolymer, P3MEEET, shows a high negative threshold voltage in accumulation mode. Thus, copolymerization with the self-dopable monomer changes the mode of operation as well as the threshold voltage substantially. Ultraviolet photoelectron spectroscopy reveals a considerable reduction of the hole injection barrier for the self-doped system P3HOTS-TMA+. Mott-Schottky analysis shows reduction in charge carrier concentration in the copolymer compared to the homopolymer. Thus, the copolymerization strategy with a self-dopable monomer is an efficient tool for tuning the degree of doping leading to low threshold voltage in OECTs. © 2024 The Author(s). Advanced Functional Materials published by Wiley-VCH GmbH.}, note = {Cited by: 0; All Open Access, Hybrid Gold Open Access}, keywords = {}, pubstate = {published}, tppubtype = {article} } Organic mixed ionic-electronic conductors with tunable doping, low threshold voltages, and air stability are crucial for bioelectronic applications. A homopolymer based on an alkoxy thiophene monomer and its copolymer with a thiophene carrying ethylene glycol side chains are synthesized and converted to self-doped conjugated polyelectrolytes, P3HOTS-TMA+, and P3HOTS-TMA+-co-P3MEEET. The self-doping occurs during the conversion to polyelectrolytes. Both polyelectrolytes show high electrical conductivity without any external dopants. UV–Vis–NIR spectroscopy and spectroelectrochemistry confirm excellent air stability of the doped state. In an organic electrochemical transistor (OECT), the P3HOTS-TMA+ operates in depletion mode, while P3HOTS-TMA+-co-P3MEEET exhibits accumulation mode of operation with low threshold voltage, both showing fast response times. On the other hand, the non-doped homopolymer, P3MEEET, shows a high negative threshold voltage in accumulation mode. Thus, copolymerization with the self-dopable monomer changes the mode of operation as well as the threshold voltage substantially. Ultraviolet photoelectron spectroscopy reveals a considerable reduction of the hole injection barrier for the self-doped system P3HOTS-TMA+. Mott-Schottky analysis shows reduction in charge carrier concentration in the copolymer compared to the homopolymer. Thus, the copolymerization strategy with a self-dopable monomer is an efficient tool for tuning the degree of doping leading to low threshold voltage in OECTs. © 2024 The Author(s). Advanced Functional Materials published by Wiley-VCH GmbH. |
Sun, Kun; Guo, Renjun; Liu, Shangpu; Guo, Dengyang; Jiang, Xiongzhuo; Huber, Linus F; Liang, Yuxin; Reus, Manuel A; Li, Zerui; Guan, Tianfu; Zhou, Jungui; Schwartzkopf, Matthias; Stranks, Samuel D; Deschler, Felix; Müller-Buschbaum, Peter Deciphering Structure and Charge Carrier Behavior in Reduced-Dimensional Perovskites Journal Article Advanced Functional Materials, 2024, ISSN: 1616301X, (Cited by: 0; All Open Access, Hybrid Gold Open Access). Abstract | Links | BibTeX | Tags: @article{Sun2024, title = {Deciphering Structure and Charge Carrier Behavior in Reduced-Dimensional Perovskites}, author = {Kun Sun and Renjun Guo and Shangpu Liu and Dengyang Guo and Xiongzhuo Jiang and Linus F Huber and Yuxin Liang and Manuel A Reus and Zerui Li and Tianfu Guan and Jungui Zhou and Matthias Schwartzkopf and Samuel D Stranks and Felix Deschler and Peter Müller-Buschbaum}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85202489750&doi=10.1002%2fadfm.202411153&partnerID=40&md5=cf3c95c8ed46c49393ce0f5de0f64520}, doi = {10.1002/adfm.202411153}, issn = {1616301X}, year = {2024}, date = {2024-01-01}, journal = {Advanced Functional Materials}, publisher = {John Wiley and Sons Inc}, abstract = {Reduced-dimensional perovskites (RDPs) have advanced perovskite optoelectronic devices due to their tunable energy landscape, structure, and orientation. However, the origin of structural and photophysical property changes when moving from low-dimensional to high-dimensional RDPs remains to be understood. This study systematically reveals structural and photophysical properties of slot-die-coated Dion-Jacobson (DJ) and Ruddlesden-Popper (RP) RDPs with different dimensionalities. RP RDPs with lower dimensionality (n = 2) exhibit a dominant n = 2 phase, preferential out-of-plane orientation, and longer charge carrier lifetime compared with DJ RDPs. In addition, the formation kinetics of RDPs with higher dimensionality (n = 4) are unraveled by in situ X-ray scattering, showing the favorable formation of the lower-n phase in RP RDPs. The formation of these lower-n phases is thermodynamically and stoichiometrically favored, while these phases are likely in the form of an “intermediate phase” which bridges the 3D-like and lower-n phases in DJ RDPs. DJ RDPs with higher dimensionality demonstrate comparable phase purity, preferential orientation, spatially vertical phase homogeneity, and longer charge carrier lifetime. As such, DJ-based perovskite solar cells (PSCs) (n = 4) demonstrate better photostability under operational conditions than RP-based PSCs. Thus, the work paves the way for the utilization of RDPs to upscale PSCs. © 2024 The Author(s). Advanced Functional Materials published by Wiley-VCH GmbH.}, note = {Cited by: 0; All Open Access, Hybrid Gold Open Access}, keywords = {}, pubstate = {published}, tppubtype = {article} } Reduced-dimensional perovskites (RDPs) have advanced perovskite optoelectronic devices due to their tunable energy landscape, structure, and orientation. However, the origin of structural and photophysical property changes when moving from low-dimensional to high-dimensional RDPs remains to be understood. This study systematically reveals structural and photophysical properties of slot-die-coated Dion-Jacobson (DJ) and Ruddlesden-Popper (RP) RDPs with different dimensionalities. RP RDPs with lower dimensionality (n = 2) exhibit a dominant n = 2 phase, preferential out-of-plane orientation, and longer charge carrier lifetime compared with DJ RDPs. In addition, the formation kinetics of RDPs with higher dimensionality (n = 4) are unraveled by in situ X-ray scattering, showing the favorable formation of the lower-n phase in RP RDPs. The formation of these lower-n phases is thermodynamically and stoichiometrically favored, while these phases are likely in the form of an “intermediate phase” which bridges the 3D-like and lower-n phases in DJ RDPs. DJ RDPs with higher dimensionality demonstrate comparable phase purity, preferential orientation, spatially vertical phase homogeneity, and longer charge carrier lifetime. As such, DJ-based perovskite solar cells (PSCs) (n = 4) demonstrate better photostability under operational conditions than RP-based PSCs. Thus, the work paves the way for the utilization of RDPs to upscale PSCs. © 2024 The Author(s). Advanced Functional Materials published by Wiley-VCH GmbH. |
Li, Zerui; Li, Yunan; Zhang, Jinsheng; Guo, Renjun; Sun, Kun; Jiang, Xiongzhuo; Wang, Peixi; Tu, Suo; Schwartzkopf, Matthias; Li, Zhiyun; Ma, Chang-Qi; Müller-Buschbaum, Peter Suppressed Degradation Process of Green-Solvent Based Organic Solar Cells Through ZnO Modification With Sulfhydryl Derivatives Journal Article Advanced Energy Materials, 2024, ISSN: 16146832, (Cited by: 0; All Open Access, Hybrid Gold Open Access). Abstract | Links | BibTeX | Tags: @article{Li2024e, title = {Suppressed Degradation Process of Green-Solvent Based Organic Solar Cells Through ZnO Modification With Sulfhydryl Derivatives}, author = {Zerui Li and Yunan Li and Jinsheng Zhang and Renjun Guo and Kun Sun and Xiongzhuo Jiang and Peixi Wang and Suo Tu and Matthias Schwartzkopf and Zhiyun Li and Chang-Qi Ma and Peter Müller-Buschbaum}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85202596295&doi=10.1002%2faenm.202402920&partnerID=40&md5=db8ab8d81b70ecba894744a882d82441}, doi = {10.1002/aenm.202402920}, issn = {16146832}, year = {2024}, date = {2024-01-01}, journal = {Advanced Energy Materials}, publisher = {John Wiley and Sons Inc}, abstract = {The interface of organic solar cells plays a crucial role in device performance and stability. Several investigations demonstrated that the interface will affect the morphology and microstructure of the active layer, which is important for device performance. Here, several mercaptan derivatives are explored in green-solvent based organic solar cells (PBDB-TF-T1: BTP-4F-12) as effective stabilization modifiers on ZnO. Operando grazing-incidence wide/small-angle X-ray scattering (GIWAXS/GISAXS) provides a deep understanding of the degradation process during operation. The degradation process is driven by a compression of the molecule stacking as well as a decrease in the donor crystallinity, besides the known decomposition of the acceptor at the interface. Solar cell degradation comprises three stages, where an unexpected component from the acceptor appears in the second stage, simultaneously with a shapely shrinking micro-structure. Furthermore, the interface modifier pentaerythritol tetrakis(3-mercapto-propionate) (PETMP) stabilizes the crystallinity of the donor as well as suppresses the decomposition of the acceptor, thus improving the device stability. The modification effect is caused by the interaction between Zn and S from the sulfhydryl groups of the mercaptan derivatives. Thus, studies of changes in the active layer morphology extend the knowledge from ex situ characterizations, broadening the understanding of the degradation mechanisms. © 2024 The Author(s). Advanced Energy Materials published by Wiley-VCH GmbH.}, note = {Cited by: 0; All Open Access, Hybrid Gold Open Access}, keywords = {}, pubstate = {published}, tppubtype = {article} } The interface of organic solar cells plays a crucial role in device performance and stability. Several investigations demonstrated that the interface will affect the morphology and microstructure of the active layer, which is important for device performance. Here, several mercaptan derivatives are explored in green-solvent based organic solar cells (PBDB-TF-T1: BTP-4F-12) as effective stabilization modifiers on ZnO. Operando grazing-incidence wide/small-angle X-ray scattering (GIWAXS/GISAXS) provides a deep understanding of the degradation process during operation. The degradation process is driven by a compression of the molecule stacking as well as a decrease in the donor crystallinity, besides the known decomposition of the acceptor at the interface. Solar cell degradation comprises three stages, where an unexpected component from the acceptor appears in the second stage, simultaneously with a shapely shrinking micro-structure. Furthermore, the interface modifier pentaerythritol tetrakis(3-mercapto-propionate) (PETMP) stabilizes the crystallinity of the donor as well as suppresses the decomposition of the acceptor, thus improving the device stability. The modification effect is caused by the interaction between Zn and S from the sulfhydryl groups of the mercaptan derivatives. Thus, studies of changes in the active layer morphology extend the knowledge from ex situ characterizations, broadening the understanding of the degradation mechanisms. © 2024 The Author(s). Advanced Energy Materials published by Wiley-VCH GmbH. |
Sirotti, Elise; Wagner, Laura I; Jiang, Chang-Ming; Eichhorn, Johanna; Munnik, Frans; Streibel, Verena; Schilcher, Maximilian J; März, Benjamin; Hegner, Franziska S; Kuhl, Matthias; Höldrich, Theresa; Müller-Caspary, Knut; Egger, David A; Sharp, Ian D Beyond Cation Disorder: Site Symmetry-Tuned Optoelectronic Properties of the Ternary Nitride Photoabsorber ZrTaN3 Journal Article Advanced Energy Materials, 2024, ISSN: 16146832, (Cited by: 0; All Open Access, Hybrid Gold Open Access). Abstract | Links | BibTeX | Tags: @article{Sirotti2024b, title = {Beyond Cation Disorder: Site Symmetry-Tuned Optoelectronic Properties of the Ternary Nitride Photoabsorber ZrTaN3}, author = {Elise Sirotti and Laura I Wagner and Chang-Ming Jiang and Johanna Eichhorn and Frans Munnik and Verena Streibel and Maximilian J Schilcher and Benjamin März and Franziska S Hegner and Matthias Kuhl and Theresa Höldrich and Knut Müller-Caspary and David A Egger and Ian D Sharp}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85200045654&doi=10.1002%2faenm.202402540&partnerID=40&md5=0920a3af1e49a334c8428c4809cec323}, doi = {10.1002/aenm.202402540}, issn = {16146832}, year = {2024}, date = {2024-01-01}, journal = {Advanced Energy Materials}, publisher = {John Wiley and Sons Inc}, abstract = {Ternary nitrides are rapidly emerging as promising compounds for optoelectronic and energy conversion applications, yet comparatively little of this vast composition space has been explored. Furthermore, the crystal structures of these compounds can exhibit a significant amount of disorder, the consequences of which are not yet well understood. Here, the deposition of bixbyite-type ZrTaN3 thin films is demonstrated by reactive magnetron co-sputtering and observed semiconducting character, with a strong optical absorption onset at 1.8 eV and significant photoactivity, with prospective application as functional photoanodes. It is found that Wyckoff-site occupancy of cations is a critical factor in determining these beneficial optoelectronic properties. First-principles calculations show that cation disorder leads to minor deviations in the total energy but modulates the bandgap by 0.5 eV, changing orbital hybridization of valence and conduction band states. In addition to demonstrating that ZrTaN3 is a promising visible light-absorbing semiconductor and active photoanode material, the findings provide important insights regarding the role of cation ordering on the electronic structure of ternary semiconductors. In particular, it is shown that not only cation order, but also the cationic Wyckoff site occupancy has a substantial impact on key optoelectronic properties, which can guide future design and synthesis of advanced semiconductors. © 2024 The Author(s). Advanced Energy Materials published by Wiley-VCH GmbH.}, note = {Cited by: 0; All Open Access, Hybrid Gold Open Access}, keywords = {}, pubstate = {published}, tppubtype = {article} } Ternary nitrides are rapidly emerging as promising compounds for optoelectronic and energy conversion applications, yet comparatively little of this vast composition space has been explored. Furthermore, the crystal structures of these compounds can exhibit a significant amount of disorder, the consequences of which are not yet well understood. Here, the deposition of bixbyite-type ZrTaN3 thin films is demonstrated by reactive magnetron co-sputtering and observed semiconducting character, with a strong optical absorption onset at 1.8 eV and significant photoactivity, with prospective application as functional photoanodes. It is found that Wyckoff-site occupancy of cations is a critical factor in determining these beneficial optoelectronic properties. First-principles calculations show that cation disorder leads to minor deviations in the total energy but modulates the bandgap by 0.5 eV, changing orbital hybridization of valence and conduction band states. In addition to demonstrating that ZrTaN3 is a promising visible light-absorbing semiconductor and active photoanode material, the findings provide important insights regarding the role of cation ordering on the electronic structure of ternary semiconductors. In particular, it is shown that not only cation order, but also the cationic Wyckoff site occupancy has a substantial impact on key optoelectronic properties, which can guide future design and synthesis of advanced semiconductors. © 2024 The Author(s). Advanced Energy Materials published by Wiley-VCH GmbH. |
Wolz, Lukas M; Grötzner, Gabriel; Rieth, Tim; Wagner, Laura I; Kuhl, Matthias; Dittloff, Johannes; Zhou, Guanda; Santra, Saswati; Streibel, Verena; Munnik, Frans; Sharp, Ian D; Eichhorn, Johanna Impact of Defects and Disorder on the Stability of Ta3N5 Photoanodes Journal Article Advanced Functional Materials, 2024, ISSN: 1616301X, (Cited by: 0; All Open Access, Hybrid Gold Open Access). Abstract | Links | BibTeX | Tags: Functional materials; Nitrogen compounds; Oxidation; Oxygen; Point defects; Tantalum compounds; Thin films; Deep-level defects; Defect concentrations; High oxygens; Oxygen content; Photo-anodes; Photoelectrode; Structural ordering; Ta3N5 photoelectrode; Thin-films; Water splitting; Stability @article{Wolz2024, title = {Impact of Defects and Disorder on the Stability of Ta3N5 Photoanodes}, author = {Lukas M Wolz and Gabriel Grötzner and Tim Rieth and Laura I Wagner and Matthias Kuhl and Johannes Dittloff and Guanda Zhou and Saswati Santra and Verena Streibel and Frans Munnik and Ian D Sharp and Johanna Eichhorn}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85198074227&doi=10.1002%2fadfm.202405532&partnerID=40&md5=cd0b1af1d85e3ab9bce8ba5e4f75117b}, doi = {10.1002/adfm.202405532}, issn = {1616301X}, year = {2024}, date = {2024-01-01}, journal = {Advanced Functional Materials}, publisher = {John Wiley and Sons Inc}, abstract = {The photoelectrochemical performance of Ta3N5 photoanodes is strongly impacted by the presence of shallow and deep defects within the bandgap. However, the role of such states in defining stability under operational conditions is not well understood. Here, a highly controllable synthesis approach is used to create homogenous Ta3N5 thin films with tailored defect concentrations to establish the relationship between atomic-scale point defects and macroscale stability. Reduced oxygen contents increase long-range structural order but lead to high concentrations of deep-level states, while higher oxygen contents result in reduced structural order but beneficially passivate deep-level defects. Despite the different defect properties, the synthesized photoelectrodes degrade similarly under water oxidation conditions due to the formation of a surface oxide layer that blocks interfacial hole injection and accelerates charge recombination. In contrast, under ferrocyanide oxidation conditions, it is found that Ta3N5 films with high oxygen concentrations exhibit long-term stability, whereas those possessing lower oxygen contents and higher deep-level defect concentrations rapidly degrade. These results indicate that deep-level defects result in rapid trapping of photocarriers and surface oxidation but that shallow oxygen donors can be introduced into Ta3N5 to enable kinetic stabilization of the interface. © 2024 The Author(s). Advanced Functional Materials published by Wiley-VCH GmbH.}, note = {Cited by: 0; All Open Access, Hybrid Gold Open Access}, keywords = {Functional materials; Nitrogen compounds; Oxidation; Oxygen; Point defects; Tantalum compounds; Thin films; Deep-level defects; Defect concentrations; High oxygens; Oxygen content; Photo-anodes; Photoelectrode; Structural ordering; Ta3N5 photoelectrode; Thin-films; Water splitting; Stability}, pubstate = {published}, tppubtype = {article} } The photoelectrochemical performance of Ta3N5 photoanodes is strongly impacted by the presence of shallow and deep defects within the bandgap. However, the role of such states in defining stability under operational conditions is not well understood. Here, a highly controllable synthesis approach is used to create homogenous Ta3N5 thin films with tailored defect concentrations to establish the relationship between atomic-scale point defects and macroscale stability. Reduced oxygen contents increase long-range structural order but lead to high concentrations of deep-level states, while higher oxygen contents result in reduced structural order but beneficially passivate deep-level defects. Despite the different defect properties, the synthesized photoelectrodes degrade similarly under water oxidation conditions due to the formation of a surface oxide layer that blocks interfacial hole injection and accelerates charge recombination. In contrast, under ferrocyanide oxidation conditions, it is found that Ta3N5 films with high oxygen concentrations exhibit long-term stability, whereas those possessing lower oxygen contents and higher deep-level defect concentrations rapidly degrade. These results indicate that deep-level defects result in rapid trapping of photocarriers and surface oxidation but that shallow oxygen donors can be introduced into Ta3N5 to enable kinetic stabilization of the interface. © 2024 The Author(s). Advanced Functional Materials published by Wiley-VCH GmbH. |
Lu, Wenzheng; Menezes, Leonardo De S; Tittl, Andreas; Ren, Haoran; Maier, Stefan A Active Huygens' metasurface based on in-situ grown conductive polymer Journal Article Nanophotonics, 13 (1), pp. 39 – 49, 2024, ISSN: 21928614, (Cited by: 4; All Open Access, Gold Open Access). Abstract | Links | BibTeX | Tags: Nanoantennas; Optical radar; Active metasurface; Beam-steering; Conductive Polymer; Electrical switching; Huygens; Metasurface; Nanoantennae; Optical efficiency; Situ grown; Switching speed; Efficiency @article{Lu202439, title = {Active Huygens' metasurface based on in-situ grown conductive polymer}, author = {Wenzheng Lu and Leonardo De S Menezes and Andreas Tittl and Haoran Ren and Stefan A Maier}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85180982631&doi=10.1515%2fnanoph-2023-0562&partnerID=40&md5=b85fb65df1761b8185f91a063cf64def}, doi = {10.1515/nanoph-2023-0562}, issn = {21928614}, year = {2024}, date = {2024-01-01}, journal = {Nanophotonics}, volume = {13}, number = {1}, pages = {39 – 49}, publisher = {Walter de Gruyter GmbH}, abstract = {Active metasurfaces provide unique advantages for on-demand light manipulation at a subwavelength scale for emerging visual applications of displays, holographic projectors, optical sensors, light detection and ranging (LiDAR). These applications put stringent requirements on switching speed, cycling duration, electro-optical controllability, modulation contrast, optical efficiency and operation voltages. However, previous demonstrations focus only on particular subsets of these key performance requirements for device implementation, while the other performance metrics have remained too low for any practical use. Here, we demonstrate an active Huygens' metasurface based on conductive polyaniline (PANI), which can be in-situ grown and optimized on the metasurface. We have achieved simultaneously on the active metasurface switching speed of 60 frame per second (fps), switching duration of more than 2000 switching cycles without noticeable degradation, hysteresis-free controllability over intermediate states, modulation contrast of over 1400 %, optical efficiency of 28 % and operation voltage range within 1 V. Such PANI-powered active metasurface design can be readily incorporated into other metasurface concepts to deliver high-reliability electrical control over its optical response, paving the way for compact and robust electro-optic metadevices. © 2023 the author(s), published by De Gruyter, Berlin/Boston.}, note = {Cited by: 4; All Open Access, Gold Open Access}, keywords = {Nanoantennas; Optical radar; Active metasurface; Beam-steering; Conductive Polymer; Electrical switching; Huygens; Metasurface; Nanoantennae; Optical efficiency; Situ grown; Switching speed; Efficiency}, pubstate = {published}, tppubtype = {article} } Active metasurfaces provide unique advantages for on-demand light manipulation at a subwavelength scale for emerging visual applications of displays, holographic projectors, optical sensors, light detection and ranging (LiDAR). These applications put stringent requirements on switching speed, cycling duration, electro-optical controllability, modulation contrast, optical efficiency and operation voltages. However, previous demonstrations focus only on particular subsets of these key performance requirements for device implementation, while the other performance metrics have remained too low for any practical use. Here, we demonstrate an active Huygens' metasurface based on conductive polyaniline (PANI), which can be in-situ grown and optimized on the metasurface. We have achieved simultaneously on the active metasurface switching speed of 60 frame per second (fps), switching duration of more than 2000 switching cycles without noticeable degradation, hysteresis-free controllability over intermediate states, modulation contrast of over 1400 %, optical efficiency of 28 % and operation voltage range within 1 V. Such PANI-powered active metasurface design can be readily incorporated into other metasurface concepts to deliver high-reliability electrical control over its optical response, paving the way for compact and robust electro-optic metadevices. © 2023 the author(s), published by De Gruyter, Berlin/Boston. |
Kang, Ziyong; Tong, Yu; Wang, Kun; Chen, Yali; Yan, Peng; Pan, Guangjiu; Müller-Buschbaum, Peter; Zhang, Lu; Yang, Yang; Wu, Jiandong; Xie, Haijiao; Liu, Shengzhong; Wang, Hongqiang Tailoring Low-Dimensional Phases for Improved Performance of 2D-3D Tin Perovskite Solar Cells Journal Article ACS Materials Letters, 6 (1), pp. 1 – 9, 2024, ISSN: 26394979, (Cited by: 3). Abstract | Links | BibTeX | Tags: Efficiency; Perovskite; Tin; Titanium nitride; Defects density; Device performance; Homoserine lactones; Lead-free perovskites; Low-dimensional phasis; Performance; Perovskite films; Precursor solutions; Transport performance; Ultra-thin; Perovskite solar cells @article{Kang20241, title = {Tailoring Low-Dimensional Phases for Improved Performance of 2D-3D Tin Perovskite Solar Cells}, author = {Ziyong Kang and Yu Tong and Kun Wang and Yali Chen and Peng Yan and Guangjiu Pan and Peter Müller-Buschbaum and Lu Zhang and Yang Yang and Jiandong Wu and Haijiao Xie and Shengzhong Liu and Hongqiang Wang}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85181018682&doi=10.1021%2facsmaterialslett.3c00929&partnerID=40&md5=33d2f41ede233f1b22168434e254337d}, doi = {10.1021/acsmaterialslett.3c00929}, issn = {26394979}, year = {2024}, date = {2024-01-01}, journal = {ACS Materials Letters}, volume = {6}, number = {1}, pages = {1 – 9}, publisher = {American Chemical Society}, abstract = {2D-3D tin perovskites are considered as promising candidates for realizing efficient lead-free perovskite solar cells (PSCs). However, the ultrathin 2D phases could unfavorably affect charge transport and device performance. In the present work, we demonstrate that the introduction of D-homoserine lactone hydrochloride (D-HLH) can tailor the low-dimensional phases and improve the quality of 2D-3D tin perovskite films. The functional group in D-HLH can interact with FA+ and I- as well as Sn2+ in the precursor solution. These interactions not only affect the formation of tin perovskite film and favor the formation of thicker 2D phases but also decrease the defect density and suppress the nonradiative recombination. As a result, the efficiency of tin PSCs is significantly improved from 7.97 to 12.45%, and the stability of the device is also enhanced. This work provides a feasible strategy to regulate the low-dimensional phases in 2D-3D tin PSCs toward realizing high efficiency. © 2023 American Chemical Society.}, note = {Cited by: 3}, keywords = {Efficiency; Perovskite; Tin; Titanium nitride; Defects density; Device performance; Homoserine lactones; Lead-free perovskites; Low-dimensional phasis; Performance; Perovskite films; Precursor solutions; Transport performance; Ultra-thin; Perovskite solar cells}, pubstate = {published}, tppubtype = {article} } 2D-3D tin perovskites are considered as promising candidates for realizing efficient lead-free perovskite solar cells (PSCs). However, the ultrathin 2D phases could unfavorably affect charge transport and device performance. In the present work, we demonstrate that the introduction of D-homoserine lactone hydrochloride (D-HLH) can tailor the low-dimensional phases and improve the quality of 2D-3D tin perovskite films. The functional group in D-HLH can interact with FA+ and I- as well as Sn2+ in the precursor solution. These interactions not only affect the formation of tin perovskite film and favor the formation of thicker 2D phases but also decrease the defect density and suppress the nonradiative recombination. As a result, the efficiency of tin PSCs is significantly improved from 7.97 to 12.45%, and the stability of the device is also enhanced. This work provides a feasible strategy to regulate the low-dimensional phases in 2D-3D tin PSCs toward realizing high efficiency. © 2023 American Chemical Society. |
Guo, Xiao; Jia, Zhenrong; Liu, Shunchang; Guo, Renjun; Jiang, Fangyuan; Shi, Yangwei; Dong, Zijing; Luo, Ran; Wang, Yu-Duan; Shi, Zhuojie; Li, Jia; Chen, Jinxi; Lee, Ling Kai; Müller-Buschbaum, Peter; Ginger, David S; Paterson, David J; Hou, Yi Stabilizing efficient wide-bandgap perovskite in perovskite-organic tandem solar cells Journal Article Joule, 2024, ISSN: 25424351, (Cited by: 1). Abstract | Links | BibTeX | Tags: 5-imidazoledicarbonitrile; Halide phase segregation; Iodine escape; Organics; Perovskite-organic tandem; Phase segregations; Power conversion efficiencies; Sub-cells; Tandem solar cells; Wide-band-gap; Perovskite, Conversion efficiency; Energy gap; Iodine; Lead compounds; Organic solar cells; Perovskite solar cells; Phase separation; X ray scattering; 2-amino-4 @article{Guo2024b, title = {Stabilizing efficient wide-bandgap perovskite in perovskite-organic tandem solar cells}, author = {Xiao Guo and Zhenrong Jia and Shunchang Liu and Renjun Guo and Fangyuan Jiang and Yangwei Shi and Zijing Dong and Ran Luo and Yu-Duan Wang and Zhuojie Shi and Jia Li and Jinxi Chen and Ling Kai Lee and Peter Müller-Buschbaum and David S Ginger and David J Paterson and Yi Hou}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85198585351&doi=10.1016%2fj.joule.2024.06.009&partnerID=40&md5=8f76312a131a5996d18067ca5866992a}, doi = {10.1016/j.joule.2024.06.009}, issn = {25424351}, year = {2024}, date = {2024-01-01}, journal = {Joule}, publisher = {Cell Press}, abstract = {Iodide and bromide integration facilitate bandgap tunability in wide-bandgap perovskites, yet high concentrations of bromide lead to halide phase segregation, adversely affecting the efficiency and stability of solar cell devices. In this work, 2-amino-4,5-imidazoledicarbonitrile (AIDCN), with highly polarized charge distribution and compact molecular configuration, is incorporated into a 1.86 eV wide-bandgap perovskite to effectively suppress photoinduced iodine escape and phase segregation. Hyperspectral photoluminescence microscopy reveals that AIDCN mitigates phase segregation under continuous laser exposure. Concurrent in situ grazing-incidence wide-angle X-ray scattering and X-ray fluorescence measurements further validate suppressed iodine escape, evidenced by a notable slowing down of lattice shrinkage and a well-maintained overall chemical composition of the perovskite under continuous illumination. Applying this approach, we achieve a power conversion efficiency (PCE) of 18.52% in 1.86 eV wide-bandgap perovskite solar cells. By integrating this perovskite subcell with the PM6:BTP-eC9 organic subcell, the tandem attains a maximum PCE of 25.13%, with a certified stabilized PCE of 23.40%. © 2024 Elsevier Inc.}, note = {Cited by: 1}, keywords = {5-imidazoledicarbonitrile; Halide phase segregation; Iodine escape; Organics; Perovskite-organic tandem; Phase segregations; Power conversion efficiencies; Sub-cells; Tandem solar cells; Wide-band-gap; Perovskite, Conversion efficiency; Energy gap; Iodine; Lead compounds; Organic solar cells; Perovskite solar cells; Phase separation; X ray scattering; 2-amino-4}, pubstate = {published}, tppubtype = {article} } Iodide and bromide integration facilitate bandgap tunability in wide-bandgap perovskites, yet high concentrations of bromide lead to halide phase segregation, adversely affecting the efficiency and stability of solar cell devices. In this work, 2-amino-4,5-imidazoledicarbonitrile (AIDCN), with highly polarized charge distribution and compact molecular configuration, is incorporated into a 1.86 eV wide-bandgap perovskite to effectively suppress photoinduced iodine escape and phase segregation. Hyperspectral photoluminescence microscopy reveals that AIDCN mitigates phase segregation under continuous laser exposure. Concurrent in situ grazing-incidence wide-angle X-ray scattering and X-ray fluorescence measurements further validate suppressed iodine escape, evidenced by a notable slowing down of lattice shrinkage and a well-maintained overall chemical composition of the perovskite under continuous illumination. Applying this approach, we achieve a power conversion efficiency (PCE) of 18.52% in 1.86 eV wide-bandgap perovskite solar cells. By integrating this perovskite subcell with the PM6:BTP-eC9 organic subcell, the tandem attains a maximum PCE of 25.13%, with a certified stabilized PCE of 23.40%. © 2024 Elsevier Inc. |
Al-Romema, Abdulaziz A; Plass, Fabian; Nizovtsev, Alexey V; Kahnt, Axel; Tsogoeva, Svetlana B Synthesis and Photo/Radiation Chemical Characterization of a New Redox-Stable Pyridine-Triazole Ligand Journal Article ChemPhysChem, 2024, ISSN: 14394235, (Cited by: 0). Abstract | Links | BibTeX | Tags: @article{Al-Romema2024, title = {Synthesis and Photo/Radiation Chemical Characterization of a New Redox-Stable Pyridine-Triazole Ligand}, author = {Abdulaziz A Al-Romema and Fabian Plass and Alexey V Nizovtsev and Axel Kahnt and Svetlana B Tsogoeva}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85199355837&doi=10.1002%2fcphc.202400273&partnerID=40&md5=c78b0f6d075ab0c0f6df2245c4101283}, doi = {10.1002/cphc.202400273}, issn = {14394235}, year = {2024}, date = {2024-01-01}, journal = {ChemPhysChem}, publisher = {John Wiley and Sons Inc}, abstract = {Photocatalysis using transition-metal complexes is widely considered the future of effective and affordable clean-air technology. In particular, redox-stable, easily accessible ligands are decisive. Here, we report a straightforward and facile synthesis of a new highly stable 2,6-bis(triazolyl)pyridine ligand, containing a nitrile moiety as a masked anchoring group, using copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) click reaction. The reported structure mimics the binding motif of uneasy to synthesize ligands. Pulse radiolysis under oxidizing and reducing conditions provided evidence for the high stability of the formed radical cation and radical anion 2,6-di(1,2,3-triazol-1-yl)-pyridine compound, thus indicating the feasibility of utilizing this as a ligand for redox active metal complexes and the sensitization of metal-oxide semiconductors (e. g., TiO2 nanoparticles or nanotubes). © 2024 The Author(s). ChemPhysChem published by Wiley-VCH GmbH.}, note = {Cited by: 0}, keywords = {}, pubstate = {published}, tppubtype = {article} } Photocatalysis using transition-metal complexes is widely considered the future of effective and affordable clean-air technology. In particular, redox-stable, easily accessible ligands are decisive. Here, we report a straightforward and facile synthesis of a new highly stable 2,6-bis(triazolyl)pyridine ligand, containing a nitrile moiety as a masked anchoring group, using copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) click reaction. The reported structure mimics the binding motif of uneasy to synthesize ligands. Pulse radiolysis under oxidizing and reducing conditions provided evidence for the high stability of the formed radical cation and radical anion 2,6-di(1,2,3-triazol-1-yl)-pyridine compound, thus indicating the feasibility of utilizing this as a ligand for redox active metal complexes and the sensitization of metal-oxide semiconductors (e. g., TiO2 nanoparticles or nanotubes). © 2024 The Author(s). ChemPhysChem published by Wiley-VCH GmbH. |
Bao, Yaqi; Li, Maoxin; Jin, Hangfan; Wang, Xiaobo; Zeng, Jie; Feng, Yang; Hui, Wei; Wang, Dourong; Gu, Lei; Zhang, Jie; Hua, Yikun; Wang, Xiao; Xu, Baomin; Chen, Wei; Wu, Zhongbin; Müller-Buschbaum, Peter; Song, Lin Directional Charge Carrier Management Enabled by Orderly Arranged Perovskite Heterodomain with Defined Size for Self-Powered Photodetectors Journal Article Advanced Functional Materials, 2024, ISSN: 1616301X, (Cited by: 0). Abstract | Links | BibTeX | Tags: Carrier transport; Heterojunctions; Photodetectors; Photons; Built-in-potential; Bulk heterojunction; Carrier separation; Charge carrier transport channel; Charge carriers transport; Heterodomain; Self-powered; Self-powered photodetector; Transport channel; Travel distance; Perovskite @article{Bao2024, title = {Directional Charge Carrier Management Enabled by Orderly Arranged Perovskite Heterodomain with Defined Size for Self-Powered Photodetectors}, author = {Yaqi Bao and Maoxin Li and Hangfan Jin and Xiaobo Wang and Jie Zeng and Yang Feng and Wei Hui and Dourong Wang and Lei Gu and Jie Zhang and Yikun Hua and Xiao Wang and Baomin Xu and Wei Chen and Zhongbin Wu and Peter Müller-Buschbaum and Lin Song}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85193513101&doi=10.1002%2fadfm.202404697&partnerID=40&md5=ca0b9b978a85c5dcf11002f1f93411f6}, doi = {10.1002/adfm.202404697}, issn = {1616301X}, year = {2024}, date = {2024-01-01}, journal = {Advanced Functional Materials}, publisher = {John Wiley and Sons Inc}, abstract = {Perovskite planar heterojunction is reported to promote charge-carrier separation at the interface due to the introduced built-in potential, leading to improved charge-carrier harvesting. However, the possible diffusion of charge carriers along the film lateral will increase their travel distance to respective electrodes, resulting in increased recombination probabilities. Constructing independent transport channels for positive and negative charge carriers individually is an efficient way to optimize the transport in the perovskite layer and thereby to achieve enhanced device performance. Here, a solution-based strategy is proposed to fabricate lateral bulk heterojunction (BHJ) by arranging methylammonium-based and formamidinium-based perovskites alternately in an ordered array with controllable domains. The structure of perovskite heterodomain directs charge carrier transport along the film normal and limits in-plane charge carrier diffusion. Moreover, the ordered perovskite array is found to greatly increase light harvesting. Consequently, the self-powered photodetector based on the perovskite heterodomain with a thickness of only 250 nm achieves a specific detectivity exceeding 1 × 1014 Jones for weak light over the whole visible light spectrum. This work provides guidance toward the fabrication of perovskite lateral BHJ using solution processing, meeting the requirements not only for charge-carrier manipulation but also for light management. © 2024 Wiley-VCH GmbH.}, note = {Cited by: 0}, keywords = {Carrier transport; Heterojunctions; Photodetectors; Photons; Built-in-potential; Bulk heterojunction; Carrier separation; Charge carrier transport channel; Charge carriers transport; Heterodomain; Self-powered; Self-powered photodetector; Transport channel; Travel distance; Perovskite}, pubstate = {published}, tppubtype = {article} } Perovskite planar heterojunction is reported to promote charge-carrier separation at the interface due to the introduced built-in potential, leading to improved charge-carrier harvesting. However, the possible diffusion of charge carriers along the film lateral will increase their travel distance to respective electrodes, resulting in increased recombination probabilities. Constructing independent transport channels for positive and negative charge carriers individually is an efficient way to optimize the transport in the perovskite layer and thereby to achieve enhanced device performance. Here, a solution-based strategy is proposed to fabricate lateral bulk heterojunction (BHJ) by arranging methylammonium-based and formamidinium-based perovskites alternately in an ordered array with controllable domains. The structure of perovskite heterodomain directs charge carrier transport along the film normal and limits in-plane charge carrier diffusion. Moreover, the ordered perovskite array is found to greatly increase light harvesting. Consequently, the self-powered photodetector based on the perovskite heterodomain with a thickness of only 250 nm achieves a specific detectivity exceeding 1 × 1014 Jones for weak light over the whole visible light spectrum. This work provides guidance toward the fabrication of perovskite lateral BHJ using solution processing, meeting the requirements not only for charge-carrier manipulation but also for light management. © 2024 Wiley-VCH GmbH. |
Schmidt, Martina; Karg, Matthias; Thelakkat, Mukundan; Brendel, Johannes C Correlating Molar Mass, π-Conjugation, and Optical Properties of Narrowly Distributed Anionic Polythiophenes in Aqueous Solutions Journal Article Macromolecular Rapid Communications, 45 (1), 2024, ISSN: 10221336, (Cited by: 0; All Open Access, Hybrid Gold Open Access). Abstract | Links | BibTeX | Tags: @article{Schmidt2024, title = {Correlating Molar Mass, π-Conjugation, and Optical Properties of Narrowly Distributed Anionic Polythiophenes in Aqueous Solutions}, author = {Martina Schmidt and Matthias Karg and Mukundan Thelakkat and Johannes C Brendel}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85167802995&doi=10.1002%2fmarc.202300396&partnerID=40&md5=25ee68f651d0dd779b6347c53ce70a27}, doi = {10.1002/marc.202300396}, issn = {10221336}, year = {2024}, date = {2024-01-01}, journal = {Macromolecular Rapid Communications}, volume = {45}, number = {1}, publisher = {John Wiley and Sons Inc}, abstract = {Polythiophene-based conjugated polyelectrolytes (CPE) are attracting increasing attention as sensor or interface materials in chemistry and biology. While cationic polythiophenes are better understood, limited structural information is available on their anionic counterparts. Limited access to well-defined polymers has made the study of structure-property relationships difficult and clear correlations have remained elusive. By combining controlled Kumada catalyst transfer polymerization with a polymer-analog substitution, regioregular and narrowly distributed poly(6-(thiophen-3-yl)hexane-1-sulfonate)s (PTHS) with tailored chain length are prepared. Analysis of their aqueous solution structures by small-angle neutron scattering (SANS) revealed a cylindrical conformation for all polymers tested, with a length close to the contour length of the polymer chains, while the estimated radii remain too small (<1.5 nm) for extensive π-stacking of the chains. The latter is particularly interesting as the longest polymer exhibits a concentration-independent structured absorption typical of crystalline polythiophenes. Increasing the ionic strength of the solution diminishes these features as the Coulomb repulsion between the charged repeat units is shielded, allowing the polymer to adopt a more coiled conformation. The extended π-conjugation, therefore, appears to be a key parameter for these unique optical features, which are not present in the corresponding cationic polythiophenes. © 2023 The Authors. Macromolecular Rapid Communications published by Wiley-VCH GmbH.}, note = {Cited by: 0; All Open Access, Hybrid Gold Open Access}, keywords = {}, pubstate = {published}, tppubtype = {article} } Polythiophene-based conjugated polyelectrolytes (CPE) are attracting increasing attention as sensor or interface materials in chemistry and biology. While cationic polythiophenes are better understood, limited structural information is available on their anionic counterparts. Limited access to well-defined polymers has made the study of structure-property relationships difficult and clear correlations have remained elusive. By combining controlled Kumada catalyst transfer polymerization with a polymer-analog substitution, regioregular and narrowly distributed poly(6-(thiophen-3-yl)hexane-1-sulfonate)s (PTHS) with tailored chain length are prepared. Analysis of their aqueous solution structures by small-angle neutron scattering (SANS) revealed a cylindrical conformation for all polymers tested, with a length close to the contour length of the polymer chains, while the estimated radii remain too small (<1.5 nm) for extensive π-stacking of the chains. The latter is particularly interesting as the longest polymer exhibits a concentration-independent structured absorption typical of crystalline polythiophenes. Increasing the ionic strength of the solution diminishes these features as the Coulomb repulsion between the charged repeat units is shielded, allowing the polymer to adopt a more coiled conformation. The extended π-conjugation, therefore, appears to be a key parameter for these unique optical features, which are not present in the corresponding cationic polythiophenes. © 2023 The Authors. Macromolecular Rapid Communications published by Wiley-VCH GmbH. |
Chen, Shouzheng; Harder, Constantin; Ribca, Iuliana; Sochor, Benedikt; Erbes, Elisabeth; Bulut, Yusuf; Pluntke, Luciana; Meinhardt, Alexander; Schummer, Bernhard; Oberthür, Markus; Keller, Thomas F; Söderberg, Daniel L; Techert, Simone A; Stierle, Andreas; Müller-Buschbaum, Peter; Johansson, Mats K G; Navarro, Julien; Roth, Stephan V Sprayed water-based lignin colloidal nanoparticle-cellulose nanofibril hybrid films with UV-blocking ability Journal Article Nanoscale Advances, 2024, ISSN: 25160230, (Cited by: 0; All Open Access, Gold Open Access). Abstract | Links | BibTeX | Tags: Cellulose films; Cellulose nanocrystals; Nanocellulose; Nanoclay; Nanoparticles; Cellulose nanofibrils; Colloidal nanoparticles; Film-forming properties; Functionals; Global climate changes; Hybrid film; Hydrophilic interfaces; Natural biopolymers; UV blocking; Water based; Nanofibers @article{Chen2024, title = {Sprayed water-based lignin colloidal nanoparticle-cellulose nanofibril hybrid films with UV-blocking ability}, author = {Shouzheng Chen and Constantin Harder and Iuliana Ribca and Benedikt Sochor and Elisabeth Erbes and Yusuf Bulut and Luciana Pluntke and Alexander Meinhardt and Bernhard Schummer and Markus Oberthür and Thomas F Keller and Daniel L Söderberg and Simone A Techert and Andreas Stierle and Peter Müller-Buschbaum and Mats K G Johansson and Julien Navarro and Stephan V Roth}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85202938425&doi=10.1039%2fd4na00191e&partnerID=40&md5=80206fed1968bc7367190c873d5d97cd}, doi = {10.1039/d4na00191e}, issn = {25160230}, year = {2024}, date = {2024-01-01}, journal = {Nanoscale Advances}, publisher = {Royal Society of Chemistry}, abstract = {In the context of global climate change, the demand for new functional materials that are sustainable and environmentally friendly is rapidly increasing. Cellulose and lignin are the two most abundant raw materials in nature, and are ideal components for functional materials. The hydrophilic interface and easy film-forming properties of cellulose nanofibrils make them excellent candidates for natural biopolymer templates and network structures. Lignin is a natural UV-shielding material, as it contains a large number of phenolic groups. In this work, we have applied two routes for spray deposition of hybrid films with different laminar structures using surface-charged cellulose nanofibrils and water-based colloidal lignin particles. As the first route, we prepare stacked colloidal lignin particles and cellulose nanofibrils hybrid film through a layer-by-layer deposition. As the second route, we spray-deposite premixed colloidal lignin particles and cellulose nanofibrils dispersion to prepare a mixed hybrid film. We find that cellulose nanofibrils act as a directing agent to dominate the arrangement of the colloidal lignin particles in a mixed system. Additionally, cellulose nanofibrils eliminate the agglomerations and thus increase the visible light transparency while retaining the UV shielding ability. Our research on these colloidal lignin and cellulose nanofibril hybrid films provides a fundamental understanding of using colloidal lignin nanoparticles as functional material on porous cellulose-based materials, for example on fabrics. © 2024 RSC}, note = {Cited by: 0; All Open Access, Gold Open Access}, keywords = {Cellulose films; Cellulose nanocrystals; Nanocellulose; Nanoclay; Nanoparticles; Cellulose nanofibrils; Colloidal nanoparticles; Film-forming properties; Functionals; Global climate changes; Hybrid film; Hydrophilic interfaces; Natural biopolymers; UV blocking; Water based; Nanofibers}, pubstate = {published}, tppubtype = {article} } In the context of global climate change, the demand for new functional materials that are sustainable and environmentally friendly is rapidly increasing. Cellulose and lignin are the two most abundant raw materials in nature, and are ideal components for functional materials. The hydrophilic interface and easy film-forming properties of cellulose nanofibrils make them excellent candidates for natural biopolymer templates and network structures. Lignin is a natural UV-shielding material, as it contains a large number of phenolic groups. In this work, we have applied two routes for spray deposition of hybrid films with different laminar structures using surface-charged cellulose nanofibrils and water-based colloidal lignin particles. As the first route, we prepare stacked colloidal lignin particles and cellulose nanofibrils hybrid film through a layer-by-layer deposition. As the second route, we spray-deposite premixed colloidal lignin particles and cellulose nanofibrils dispersion to prepare a mixed hybrid film. We find that cellulose nanofibrils act as a directing agent to dominate the arrangement of the colloidal lignin particles in a mixed system. Additionally, cellulose nanofibrils eliminate the agglomerations and thus increase the visible light transparency while retaining the UV shielding ability. Our research on these colloidal lignin and cellulose nanofibril hybrid films provides a fundamental understanding of using colloidal lignin nanoparticles as functional material on porous cellulose-based materials, for example on fabrics. © 2024 RSC |
Betker, Marie; Erichlandwehr, Tim; Sochor, Benedikt; Erbes, Elisabeth; Kurmanbay, Alisher; Alon, Yamit; Li, Yanan; Fernandez-Cuesta, Irene; Müller-Buschbaum, Peter; Techert, Simone A; Söderberg, Daniel L; Roth, Stephan V Micrometer-Thin Nanocellulose Foils for 3D Organic Electronics Journal Article Advanced Functional Materials, 2024, ISSN: 1616301X, (Cited by: 0; All Open Access, Hybrid Gold Open Access). Abstract | Links | BibTeX | Tags: Biodegradability; Biodegradable polymers; Conducting polymers; Deposition; Functional materials; Nanocellulose; Spray nozzles; 3d material; Mechanical; Nano-cellulose; Optical transparency; Organic electronics; Property; Spray deposition; Substrate material; Thin-films; Ultra-thin; Substrates @article{Betker2024, title = {Micrometer-Thin Nanocellulose Foils for 3D Organic Electronics}, author = {Marie Betker and Tim Erichlandwehr and Benedikt Sochor and Elisabeth Erbes and Alisher Kurmanbay and Yamit Alon and Yanan Li and Irene Fernandez-Cuesta and Peter Müller-Buschbaum and Simone A Techert and Daniel L Söderberg and Stephan V Roth}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85193521275&doi=10.1002%2fadfm.202403952&partnerID=40&md5=e74d8059dea72b93fe3121f6cbb1266c}, doi = {10.1002/adfm.202403952}, issn = {1616301X}, year = {2024}, date = {2024-01-01}, journal = {Advanced Functional Materials}, publisher = {John Wiley and Sons Inc}, abstract = {Cellulose is a natural polymer with great properties such as high optical transparency and mechanical strength, flexibility, and biodegradability. Hence, cellulose-based foils are suitable for the replacement of synthetic polymers as substrate materials in organic electronics. This article reports the fabrication of ultrathin, free-standing cellulose foils by spraying aqueous 2,2,6,6-tetramethylpiperidine-1-oxyl-nanocellulose (TEMPO) fibrils ink layer-by-layer on a hot substrate using a movable spray nozzle. The resulting foils are only 2 ± 1 µm in thickness with an average basis weight of 1.9 g m−2, which ranges in the same scale as the world's thinnest paper. The suitability of these ultra-thin nanocellulose foils as a sustainable substrate material for organic electronic applications is demonstrated by testing the foils resistance against organic solvents. Furthermore, silver nanowires (AgNWs) and the blend poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) are integrated into the foils, and the foils are molded into 3D paper structures in order to create conductive, paper-based building blocks for organic electronics. © 2024 The Authors. Advanced Functional Materials published by Wiley-VCH GmbH.}, note = {Cited by: 0; All Open Access, Hybrid Gold Open Access}, keywords = {Biodegradability; Biodegradable polymers; Conducting polymers; Deposition; Functional materials; Nanocellulose; Spray nozzles; 3d material; Mechanical; Nano-cellulose; Optical transparency; Organic electronics; Property; Spray deposition; Substrate material; Thin-films; Ultra-thin; Substrates}, pubstate = {published}, tppubtype = {article} } Cellulose is a natural polymer with great properties such as high optical transparency and mechanical strength, flexibility, and biodegradability. Hence, cellulose-based foils are suitable for the replacement of synthetic polymers as substrate materials in organic electronics. This article reports the fabrication of ultrathin, free-standing cellulose foils by spraying aqueous 2,2,6,6-tetramethylpiperidine-1-oxyl-nanocellulose (TEMPO) fibrils ink layer-by-layer on a hot substrate using a movable spray nozzle. The resulting foils are only 2 ± 1 µm in thickness with an average basis weight of 1.9 g m−2, which ranges in the same scale as the world's thinnest paper. The suitability of these ultra-thin nanocellulose foils as a sustainable substrate material for organic electronic applications is demonstrated by testing the foils resistance against organic solvents. Furthermore, silver nanowires (AgNWs) and the blend poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) are integrated into the foils, and the foils are molded into 3D paper structures in order to create conductive, paper-based building blocks for organic electronics. © 2024 The Authors. Advanced Functional Materials published by Wiley-VCH GmbH. |
Aigner, Andreas; Ligmajer, Filip; Rovenská, Katarína; Holobrádek, Jakub; Idesová, Beáta; Maier, Stefan A; Tittl, Andreas; de Menezes, Leonardo S Engineering of Active and Passive Loss in High-Quality-Factor Vanadium Dioxide-Based BIC Metasurfaces Journal Article Nano Letters, 2024, ISSN: 15306984, (Cited by: 0; All Open Access, Hybrid Gold Open Access). Abstract | Links | BibTeX | Tags: oxide; vanadium; Active metasurface; Bound state in the continuum; Bound-states; Loss tunability; Metasurface; Near fields; Near-field tunability; Tunabilities; Vanadium dioxide; article; controlled study; nanophotonics; temperature; Nanophotonics @article{Aigner2024, title = {Engineering of Active and Passive Loss in High-Quality-Factor Vanadium Dioxide-Based BIC Metasurfaces}, author = {Andreas Aigner and Filip Ligmajer and Katarína Rovenská and Jakub Holobrádek and Beáta Idesová and Stefan A Maier and Andreas Tittl and Leonardo de S. Menezes}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85202647685&doi=10.1021%2facs.nanolett.4c01703&partnerID=40&md5=a06760cb7b7f4e006a623ff6232c4499}, doi = {10.1021/acs.nanolett.4c01703}, issn = {15306984}, year = {2024}, date = {2024-01-01}, journal = {Nano Letters}, publisher = {American Chemical Society}, abstract = {Active functionalities of metasurfaces are of growing interest in nanophotonics. The main strategy employed to date is spectral resonance tuning affecting predominantly the far-field response. However, this barely influences other essential resonance properties like near-field enhancement, signal modulation, quality factor, and absorbance, which are all vital for numerous applications. Here we introduce an active metasurface approach that combines temperature-tunable losses in vanadium dioxide with far-field coupling tunable symmetry-protected bound states in the continuum. This method enables exceptional precision in independently controlling both radiative and nonradiative losses. Consequently, it allows for the adjustment of both the far-field response and, notably, the near-field characteristics like local field enhancement and absorbance. We experimentally demonstrate continuous tuning from under- through critical- to overcoupling, achieving quality factors of 200 and a relative switching contrast of 78%. Our research marks a significant step toward highly tunable metasurfaces, controlling both near- and far-field properties. © 2024 The Authors. Published by American Chemical Society.}, note = {Cited by: 0; All Open Access, Hybrid Gold Open Access}, keywords = {oxide; vanadium; Active metasurface; Bound state in the continuum; Bound-states; Loss tunability; Metasurface; Near fields; Near-field tunability; Tunabilities; Vanadium dioxide; article; controlled study; nanophotonics; temperature; Nanophotonics}, pubstate = {published}, tppubtype = {article} } Active functionalities of metasurfaces are of growing interest in nanophotonics. The main strategy employed to date is spectral resonance tuning affecting predominantly the far-field response. However, this barely influences other essential resonance properties like near-field enhancement, signal modulation, quality factor, and absorbance, which are all vital for numerous applications. Here we introduce an active metasurface approach that combines temperature-tunable losses in vanadium dioxide with far-field coupling tunable symmetry-protected bound states in the continuum. This method enables exceptional precision in independently controlling both radiative and nonradiative losses. Consequently, it allows for the adjustment of both the far-field response and, notably, the near-field characteristics like local field enhancement and absorbance. We experimentally demonstrate continuous tuning from under- through critical- to overcoupling, achieving quality factors of 200 and a relative switching contrast of 78%. Our research marks a significant step toward highly tunable metasurfaces, controlling both near- and far-field properties. © 2024 The Authors. Published by American Chemical Society. |
Valente, Gonçalo; Dantas, Raquel; Ferreira, Pedro; Grieco, Rebecca; Patil, Nagaraj; Guillem-Navajas, Ana; Miguel, David Rodríguez-San; Zamora, Félix; Guntermann, Roman; Bein, Thomas; Rocha, João; Braga, Helena M; Strutyński, Karol; Melle-Franco, Manuel; Marcilla, Rebeca; Souto, Manuel Tetrathiafulvalene-based covalent organic frameworks as high-voltage organic cathodes for lithium batteries Journal Article Journal of Materials Chemistry A, 2024, ISSN: 20507488, (Cited by: 0). Abstract | Links | BibTeX | Tags: Lithium compounds; Lithium-ion batteries; Redox reactions; Covalent organic frameworks; Electrode material; High-voltages; Ion batteries; Metals ions; Organic cathodes; Redox-active; Tetrathiafulvalenes; Tunables; Two-dimensional; Electrochemical electrodes @article{Valente2024, title = {Tetrathiafulvalene-based covalent organic frameworks as high-voltage organic cathodes for lithium batteries}, author = {Gonçalo Valente and Raquel Dantas and Pedro Ferreira and Rebecca Grieco and Nagaraj Patil and Ana Guillem-Navajas and David Rodríguez-San Miguel and Félix Zamora and Roman Guntermann and Thomas Bein and João Rocha and Helena M Braga and Karol Strutyński and Manuel Melle-Franco and Rebeca Marcilla and Manuel Souto}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85201428063&doi=10.1039%2fd4ta04576a&partnerID=40&md5=961b9f8d9b2a7e85f5fa41fbc3c5a440}, doi = {10.1039/d4ta04576a}, issn = {20507488}, year = {2024}, date = {2024-01-01}, journal = {Journal of Materials Chemistry A}, publisher = {Royal Society of Chemistry}, abstract = {Redox-active covalent organic frameworks (COFs) are promising electrode materials for metal-ion batteries owing to their tunable electrochemical properties, adjustable structure, and resource availability. Herein, we report a series of two-dimensional tetrathiafulvalene (TTF)-based COFs incorporating different organic linkers between the electroactive moieties. These COFs were investigated as p-type organic cathode materials for lithium-organic batteries. The electrical conductivity of both neutral and doped TTF-COFs was measured using a van der Pauw setup, and their electronic structures were investigated through quantum-chemical calculations. Binder-free buckypaper TTF-based electrodes were prepared and systematically tested as organic cathodes in lithium half-cells. The results revealed high average discharge potentials (∼3.6 V vs. Li/Li+) and consistent cycling stability (80% capacity retention after 400 cycles at 2C) for the three TTF-COF electrodes. In addition, the specific capacity, rate capability, and kinetics varied depending on the structure of the framework. Our results highlight the potential of TTF-COFs as high-voltage organic cathodes for metal-ion batteries and emphasize the importance of molecular design in optimizing their electrochemical performance. © 2024 The Royal Society of Chemistry.}, note = {Cited by: 0}, keywords = {Lithium compounds; Lithium-ion batteries; Redox reactions; Covalent organic frameworks; Electrode material; High-voltages; Ion batteries; Metals ions; Organic cathodes; Redox-active; Tetrathiafulvalenes; Tunables; Two-dimensional; Electrochemical electrodes}, pubstate = {published}, tppubtype = {article} } Redox-active covalent organic frameworks (COFs) are promising electrode materials for metal-ion batteries owing to their tunable electrochemical properties, adjustable structure, and resource availability. Herein, we report a series of two-dimensional tetrathiafulvalene (TTF)-based COFs incorporating different organic linkers between the electroactive moieties. These COFs were investigated as p-type organic cathode materials for lithium-organic batteries. The electrical conductivity of both neutral and doped TTF-COFs was measured using a van der Pauw setup, and their electronic structures were investigated through quantum-chemical calculations. Binder-free buckypaper TTF-based electrodes were prepared and systematically tested as organic cathodes in lithium half-cells. The results revealed high average discharge potentials (∼3.6 V vs. Li/Li+) and consistent cycling stability (80% capacity retention after 400 cycles at 2C) for the three TTF-COF electrodes. In addition, the specific capacity, rate capability, and kinetics varied depending on the structure of the framework. Our results highlight the potential of TTF-COFs as high-voltage organic cathodes for metal-ion batteries and emphasize the importance of molecular design in optimizing their electrochemical performance. © 2024 The Royal Society of Chemistry. |
Sirotti, Elise; Böhm, Stefan; Sharp, Ian D Ultrastable Zn3N2 Thin Films via Integration of Amorphous GaN Protection Layers Journal Article Advanced Materials Interfaces, 11 (22), 2024, ISSN: 21967350, (Cited by: 0). Abstract | Links | BibTeX | Tags: @article{Sirotti2024, title = {Ultrastable Zn3N2 Thin Films via Integration of Amorphous GaN Protection Layers}, author = {Elise Sirotti and Stefan Böhm and Ian D Sharp}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85196511694&doi=10.1002%2fadmi.202400214&partnerID=40&md5=dc119cc28d4f1c2ccb3c5d6edda495f7}, doi = {10.1002/admi.202400214}, issn = {21967350}, year = {2024}, date = {2024-01-01}, journal = {Advanced Materials Interfaces}, volume = {11}, number = {22}, publisher = {John Wiley and Sons Inc}, abstract = {Zinc nitride (Zn3N2) is a promising semiconductor for a range of optoelectronic and energy conversion applications, offering a direct bandgap of 1.0 eV, large carrier mobilities, and abundant constituent elements. However, the material is prone to bulk oxidation in ambient environments, which has thus far impeded its practical deployment. While previous approaches have focused on stabilizing the material via integration of ZnO surface layers, these strategies introduce additional challenges regarding elevated processing temperatures and limited control of interface properties. In this study, it is shown that amorphous GaN thin films can serve as highly stable protection layers on Zn3N2 surfaces and can be deposited at the same growth temperature and in the same deposition system as the underlying semiconductor. The GaN-capped Zn3N2 structures exhibit long-term stability, surviving over 3 years of exposure to ambient conditions with no discernible alterations in composition, structure, or electrical properties. Notably, the amorphous GaN coatings can even impede Zn3N2 oxidation under prolonged aqueous exposure. Thus, this study offers a solution to stabilize Zn3N2 in ambient conditions, providing a viable pathway to its utilization in robust and high-performance electronic devices, such as thin film transistors and solar energy conversion systems. © 2024 The Author(s). Advanced Materials Interfaces published by Wiley-VCH GmbH.}, note = {Cited by: 0}, keywords = {}, pubstate = {published}, tppubtype = {article} } Zinc nitride (Zn3N2) is a promising semiconductor for a range of optoelectronic and energy conversion applications, offering a direct bandgap of 1.0 eV, large carrier mobilities, and abundant constituent elements. However, the material is prone to bulk oxidation in ambient environments, which has thus far impeded its practical deployment. While previous approaches have focused on stabilizing the material via integration of ZnO surface layers, these strategies introduce additional challenges regarding elevated processing temperatures and limited control of interface properties. In this study, it is shown that amorphous GaN thin films can serve as highly stable protection layers on Zn3N2 surfaces and can be deposited at the same growth temperature and in the same deposition system as the underlying semiconductor. The GaN-capped Zn3N2 structures exhibit long-term stability, surviving over 3 years of exposure to ambient conditions with no discernible alterations in composition, structure, or electrical properties. Notably, the amorphous GaN coatings can even impede Zn3N2 oxidation under prolonged aqueous exposure. Thus, this study offers a solution to stabilize Zn3N2 in ambient conditions, providing a viable pathway to its utilization in robust and high-performance electronic devices, such as thin film transistors and solar energy conversion systems. © 2024 The Author(s). Advanced Materials Interfaces published by Wiley-VCH GmbH. |
Berger, Luca M; Barkey, Martin; Maier, Stefan A; Tittl, Andreas Metallic and All-Dielectric Metasurfaces Sustaining Displacement-Mediated Bound States in the Continuum Journal Article Advanced Optical Materials, 12 (5), 2024, ISSN: 21951071, (Cited by: 6; All Open Access, Green Open Access, Hybrid Gold Open Access). Abstract | Links | BibTeX | Tags: Nanophotonics; Photonic devices; Angular-robust; Bound state in the continuum; Bound-states; Metallics; Metasurface; Microscope objective; Mid-IR spectroscopy; Reflective microscope objective; Reflective microscopes; Superlattice; Incident light @article{Berger2024, title = {Metallic and All-Dielectric Metasurfaces Sustaining Displacement-Mediated Bound States in the Continuum}, author = {Luca M Berger and Martin Barkey and Stefan A Maier and Andreas Tittl}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85169339120&doi=10.1002%2fadom.202301269&partnerID=40&md5=e2109c06d6b9ff2112970d07bbc33976}, doi = {10.1002/adom.202301269}, issn = {21951071}, year = {2024}, date = {2024-01-01}, journal = {Advanced Optical Materials}, volume = {12}, number = {5}, publisher = {John Wiley and Sons Inc}, abstract = {Bound states in the continuum (BICs) are localized electromagnetic modes within the continuous spectrum of radiating waves. Due to their infinite lifetimes without radiation losses, BICs are driving research directions in lasing, non-linear optical processes, and sensing. However, conventional methods for converting BICs into leaky resonances, or quasi-BICs, with high-quality factors typically rely on breaking the in-plane inversion symmetry of the metasurface and often result in resonances that are strongly dependent on the angle of the incident light, making them unsuitable for many practical applications. Here, an emerging class of BIC-driven metasurfaces is numerically analyzed and experimentally demonstrated, where the coupling to the far field is controlled by the displacement of individual resonators. In particular, both all-dielectric and metallic as well as positive and inverse displacement-mediated metasurfaces sustaining angular-robust quasi-BICs are investigated in the mid-infrared spectral region. Their optical behavior with regard to changes in the angle of incidence is investigated and experimentally shows their superior performance compared to two conventional alternatives: silicon-based tilted ellipses and cylindrical nanoholes in gold. These findings are anticipated to open exciting perspectives for bio-sensing, conformal optical devices, and photonic devices using focused light. © 2023 The Authors. Advanced Optical Materials published by Wiley-VCH GmbH.}, note = {Cited by: 6; All Open Access, Green Open Access, Hybrid Gold Open Access}, keywords = {Nanophotonics; Photonic devices; Angular-robust; Bound state in the continuum; Bound-states; Metallics; Metasurface; Microscope objective; Mid-IR spectroscopy; Reflective microscope objective; Reflective microscopes; Superlattice; Incident light}, pubstate = {published}, tppubtype = {article} } Bound states in the continuum (BICs) are localized electromagnetic modes within the continuous spectrum of radiating waves. Due to their infinite lifetimes without radiation losses, BICs are driving research directions in lasing, non-linear optical processes, and sensing. However, conventional methods for converting BICs into leaky resonances, or quasi-BICs, with high-quality factors typically rely on breaking the in-plane inversion symmetry of the metasurface and often result in resonances that are strongly dependent on the angle of the incident light, making them unsuitable for many practical applications. Here, an emerging class of BIC-driven metasurfaces is numerically analyzed and experimentally demonstrated, where the coupling to the far field is controlled by the displacement of individual resonators. In particular, both all-dielectric and metallic as well as positive and inverse displacement-mediated metasurfaces sustaining angular-robust quasi-BICs are investigated in the mid-infrared spectral region. Their optical behavior with regard to changes in the angle of incidence is investigated and experimentally shows their superior performance compared to two conventional alternatives: silicon-based tilted ellipses and cylindrical nanoholes in gold. These findings are anticipated to open exciting perspectives for bio-sensing, conformal optical devices, and photonic devices using focused light. © 2023 The Authors. Advanced Optical Materials published by Wiley-VCH GmbH. |
Derelli, Davide; Frank, Kilian; Grote, Lukas; Mancini, Federica; Dippel, Ann-Christin; Gutowski, Olof; Nickel, Bert; Koziej, Dorota Direct Synthesis of CuPd Icosahedra Supercrystals Studied by In Situ X-Ray Scattering Journal Article Small, 20 (32), 2024, ISSN: 16136810, (Cited by: 0; All Open Access, Hybrid Gold Open Access). Abstract | Links | BibTeX | Tags: @article{Derelli2024, title = {Direct Synthesis of CuPd Icosahedra Supercrystals Studied by In Situ X-Ray Scattering}, author = {Davide Derelli and Kilian Frank and Lukas Grote and Federica Mancini and Ann-Christin Dippel and Olof Gutowski and Bert Nickel and Dorota Koziej}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85188518964&doi=10.1002%2fsmll.202311714&partnerID=40&md5=95bcc8e6ed98322bfb411c2169f05879}, doi = {10.1002/smll.202311714}, issn = {16136810}, year = {2024}, date = {2024-01-01}, journal = {Small}, volume = {20}, number = {32}, publisher = {John Wiley and Sons Inc}, abstract = {Nanocrystal self-assembly into supercrystals provides a versatile platform for creating novel materials and devices with tailored properties. While common self-assembly strategies imply the use of purified nanoparticles after synthesis, conversion of chemical precursors directly into nanocrystals and then supercrystals in simple procedures has been rarely reported. Here, the nucleation and growth of CuPd icosahedra and their consecutive assembly into large closed-packed face-centered cubic (fcc) supercrystals are studied. To this end, the study simultaneously and in situ measures X-ray total scattering with pair distribution function analysis (TS-PDF) and small-angle X-ray scattering (SAXS). It is found that the supercrystals' formation is preceded by an intermediate dense phase of nanocrystals displaying short-range order (SRO). It is further shown that the organization of oleic acid/oleylamine surfactants into lamellar structures likely drives the emergence of the SRO phase and later of the supercrystals by reducing the volume accessible to particle diffusion. The supercrystals' formation as well as their disassembly are triggered by temperature. The study demonstrates that ordering of solvent molecules can be crucial in the direct synthesis of supercrystals. The study also provides a general approach to investigate novel preparation routes of supercrystals in situ and across several length scales via X-ray scattering. © 2024 The Authors. Small published by Wiley-VCH GmbH.}, note = {Cited by: 0; All Open Access, Hybrid Gold Open Access}, keywords = {}, pubstate = {published}, tppubtype = {article} } Nanocrystal self-assembly into supercrystals provides a versatile platform for creating novel materials and devices with tailored properties. While common self-assembly strategies imply the use of purified nanoparticles after synthesis, conversion of chemical precursors directly into nanocrystals and then supercrystals in simple procedures has been rarely reported. Here, the nucleation and growth of CuPd icosahedra and their consecutive assembly into large closed-packed face-centered cubic (fcc) supercrystals are studied. To this end, the study simultaneously and in situ measures X-ray total scattering with pair distribution function analysis (TS-PDF) and small-angle X-ray scattering (SAXS). It is found that the supercrystals' formation is preceded by an intermediate dense phase of nanocrystals displaying short-range order (SRO). It is further shown that the organization of oleic acid/oleylamine surfactants into lamellar structures likely drives the emergence of the SRO phase and later of the supercrystals by reducing the volume accessible to particle diffusion. The supercrystals' formation as well as their disassembly are triggered by temperature. The study demonstrates that ordering of solvent molecules can be crucial in the direct synthesis of supercrystals. The study also provides a general approach to investigate novel preparation routes of supercrystals in situ and across several length scales via X-ray scattering. © 2024 The Authors. Small published by Wiley-VCH GmbH. |
Jan, Pei-En; Liang, Hao-Chi; Cheng, Ren-Wei; Greve, Christopher R; Chuang, Yung-Tang; Chiu, Yung-Ling; Tan, Guang-Hsun; Elsenety, Mohamed M; Chang, Chih-Li; Dorrah, Dalia M; Lai, Hoong-Lien; Chiu, Po-Wei; Sun, Sheng-Yuan; Li, Yun-Li; Herzig, Eva M; Chou, Ho-Hsiu; Lin, Hao-Wu Advanced Functional Materials, 2024, ISSN: 1616301X, (Cited by: 0). Abstract | Links | BibTeX | Tags: @article{Jan2024, title = {Molecular Design Strategy for Meta-Substituted Aromatic Organic Halides in Zero-Lead-Release Halide Perovskites with Efficient Waterproof Light Emission}, author = {Pei-En Jan and Hao-Chi Liang and Ren-Wei Cheng and Christopher R Greve and Yung-Tang Chuang and Yung-Ling Chiu and Guang-Hsun Tan and Mohamed M Elsenety and Chih-Li Chang and Dalia M Dorrah and Hoong-Lien Lai and Po-Wei Chiu and Sheng-Yuan Sun and Yun-Li Li and Eva M Herzig and Ho-Hsiu Chou and Hao-Wu Lin}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85203043862&doi=10.1002%2fadfm.202408323&partnerID=40&md5=a4d8aa1813df5d142bfe44e08872c17a}, doi = {10.1002/adfm.202408323}, issn = {1616301X}, year = {2024}, date = {2024-01-01}, journal = {Advanced Functional Materials}, publisher = {John Wiley and Sons Inc}, abstract = {Halide perovskites have received an immense attention in the field of optoelectronics due to their outstanding photophysical properties. But so far, lead-based halide perovskites still account for most of the research, which raises concerns due to lead toxicity. Herein, a new design strategy is proposed utilizing a super large, energetically higher singlet and triplet energy levels aromatic organic cation to incorporate into the perovskite structure, forming ultra-stable high-performance 2D/3D (quasi-2D) perovskite. The judicious molecular design of connecting all the phenyl groups at their meta sites ensures the simultaneous achievement of a large molecular weight and high singlet and triplet energy levels. The resulting quasi-2D perovskite thin films not only exhibits excellent emission properties but also, surprisingly, show long-term waterproof-level stability. The robustness of these perovskites is confirmed by their extraordinary emission stability upon direct water immersion and almost undetectable lead release in water. Proof-of-concept of a water-resistant color conversion-type perovskite near-infrared (NIR) light-emitting diode (LED) is demonstrated, showing high external quantum efficiency (EQE) and power conversion efficiency (PCE) of 20.5% and 13.3%, respectively. It is believed these results and strategy pave a new way for realizing environmentally friendly lead halide materials and devices. © 2024 Wiley-VCH GmbH.}, note = {Cited by: 0}, keywords = {}, pubstate = {published}, tppubtype = {article} } Halide perovskites have received an immense attention in the field of optoelectronics due to their outstanding photophysical properties. But so far, lead-based halide perovskites still account for most of the research, which raises concerns due to lead toxicity. Herein, a new design strategy is proposed utilizing a super large, energetically higher singlet and triplet energy levels aromatic organic cation to incorporate into the perovskite structure, forming ultra-stable high-performance 2D/3D (quasi-2D) perovskite. The judicious molecular design of connecting all the phenyl groups at their meta sites ensures the simultaneous achievement of a large molecular weight and high singlet and triplet energy levels. The resulting quasi-2D perovskite thin films not only exhibits excellent emission properties but also, surprisingly, show long-term waterproof-level stability. The robustness of these perovskites is confirmed by their extraordinary emission stability upon direct water immersion and almost undetectable lead release in water. Proof-of-concept of a water-resistant color conversion-type perovskite near-infrared (NIR) light-emitting diode (LED) is demonstrated, showing high external quantum efficiency (EQE) and power conversion efficiency (PCE) of 20.5% and 13.3%, respectively. It is believed these results and strategy pave a new way for realizing environmentally friendly lead halide materials and devices. © 2024 Wiley-VCH GmbH. |
Reus, Manuel A; Reb, Lennart K; Kosbahn, David P; Roth, Stephan V; Müller-Buschbaum, Peter INSIGHT: in situ heuristic tool for the efficient reduction of grazing-incidence X-ray scattering data Journal Article Journal of Applied Crystallography, 57 , pp. 509 – 528, 2024, ISSN: 00218898, (Cited by: 5; All Open Access, Hybrid Gold Open Access). Abstract | Links | BibTeX | Tags: @article{Reus2024509, title = {INSIGHT: in situ heuristic tool for the efficient reduction of grazing-incidence X-ray scattering data}, author = {Manuel A Reus and Lennart K Reb and David P Kosbahn and Stephan V Roth and Peter Müller-Buschbaum}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85189931954&doi=10.1107%2fS1600576723011159&partnerID=40&md5=a928626dbb33d73f92d7880e27a75d81}, doi = {10.1107/S1600576723011159}, issn = {00218898}, year = {2024}, date = {2024-01-01}, journal = {Journal of Applied Crystallography}, volume = {57}, pages = {509 – 528}, publisher = {International Union of Crystallography}, abstract = {INSIGHT is a Python-based software tool for processing and reducing 2D grazing-incidence wide- and small-angle X-ray scattering (GIWAXS/GISAXS) data. It offers the geometric transformation of the 2D GIWAXS/GISAXS detector image to reciprocal space, including vectorized and parallelized pixelwise intensity correction calculations. An explicit focus on efficient data management and batch processing enables full control of large time-resolved synchrotron and laboratory data sets for a detailed analysis of kinetic GIWAXS/ GISAXS studies of thin films. It processes data acquired with arbitrarily rotated detectors and performs vertical, horizontal, azimuthal and radial cuts in reciprocal space. It further allows crystallographic indexing and GIWAXS pattern simulation, and provides various plotting and export functionalities. Customized scripting offers a one-step solution to reduce, process, analyze and export findings of large in situ and operando data sets. © 2024 International Union of Crystallography. All rights reserved.}, note = {Cited by: 5; All Open Access, Hybrid Gold Open Access}, keywords = {}, pubstate = {published}, tppubtype = {article} } INSIGHT is a Python-based software tool for processing and reducing 2D grazing-incidence wide- and small-angle X-ray scattering (GIWAXS/GISAXS) data. It offers the geometric transformation of the 2D GIWAXS/GISAXS detector image to reciprocal space, including vectorized and parallelized pixelwise intensity correction calculations. An explicit focus on efficient data management and batch processing enables full control of large time-resolved synchrotron and laboratory data sets for a detailed analysis of kinetic GIWAXS/ GISAXS studies of thin films. It processes data acquired with arbitrarily rotated detectors and performs vertical, horizontal, azimuthal and radial cuts in reciprocal space. It further allows crystallographic indexing and GIWAXS pattern simulation, and provides various plotting and export functionalities. Customized scripting offers a one-step solution to reduce, process, analyze and export findings of large in situ and operando data sets. © 2024 International Union of Crystallography. All rights reserved. |
Almora, Osbel; Cabrera, Carlos I; Erten-Ela, Sule; Forberich, Karen; Fukuda, Kenjiro; Guo, Fei; Hauch, Jens; Ho-Baillie, Anita W Y; Jacobsson, Jesper T; Janssen, Rene A J; Kirchartz, Thomas; Loi, Maria A; Mathew, Xavier; Mitzi, David B; Nazeeruddin, Mohammad K; Paetzold, Ulrich W; Rand, Barry P; Rau, Uwe; Someya, Takao; Unger, Eva; Vaillant-Roca, Lídice; Brabec, Christoph J Device Performance of Emerging Photovoltaic Materials (Version 4) Journal Article Advanced Energy Materials, 14 (4), 2024, ISSN: 16146832, (Cited by: 8; All Open Access, Hybrid Gold Open Access). Abstract | Links | BibTeX | Tags: @article{Almora2024, title = {Device Performance of Emerging Photovoltaic Materials (Version 4)}, author = {Osbel Almora and Carlos I Cabrera and Sule Erten-Ela and Karen Forberich and Kenjiro Fukuda and Fei Guo and Jens Hauch and Anita W Y Ho-Baillie and Jesper T Jacobsson and Rene A J Janssen and Thomas Kirchartz and Maria A Loi and Xavier Mathew and David B Mitzi and Mohammad K Nazeeruddin and Ulrich W Paetzold and Barry P Rand and Uwe Rau and Takao Someya and Eva Unger and Lídice Vaillant-Roca and Christoph J Brabec}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85179733522&doi=10.1002%2faenm.202303173&partnerID=40&md5=1c0215d482802ecd01505122d7519361}, doi = {10.1002/aenm.202303173}, issn = {16146832}, year = {2024}, date = {2024-01-01}, journal = {Advanced Energy Materials}, volume = {14}, number = {4}, publisher = {John Wiley and Sons Inc}, abstract = {Following the 3rd release of the “Emerging PV reports”, the best achievements in the performance of emerging photovoltaic (e-PV) devices in diverse e-PV research subjects are summarized, as reported in peer-reviewed articles in academic journals since August 2022. Updated graphs, tables, and analyses are provided with several performance parameters, such as power conversion efficiency, open-circuit voltage, short-circuit current density, fill factor, light utilization efficiency, and stability test energy yield. These parameters are presented as a function of the photovoltaic bandgap energy and the average visible transmittance for each technology and application, and are put into perspective using, for example, the detailed balance efficiency limit. The 4th installment of the “Emerging PV reports” discusses the “PV emergence” classification with respect to the “PV technology generations” and “PV research waves” and highlights the latest device performance progress in multijunction and flexible photovoltaics. Additionally, Dale-Scarpulla's plots of efficiency-effort in terms of cumulative academic publication count are also introduced. © 2023 Wiley-VCH GmbH.}, note = {Cited by: 8; All Open Access, Hybrid Gold Open Access}, keywords = {}, pubstate = {published}, tppubtype = {article} } Following the 3rd release of the “Emerging PV reports”, the best achievements in the performance of emerging photovoltaic (e-PV) devices in diverse e-PV research subjects are summarized, as reported in peer-reviewed articles in academic journals since August 2022. Updated graphs, tables, and analyses are provided with several performance parameters, such as power conversion efficiency, open-circuit voltage, short-circuit current density, fill factor, light utilization efficiency, and stability test energy yield. These parameters are presented as a function of the photovoltaic bandgap energy and the average visible transmittance for each technology and application, and are put into perspective using, for example, the detailed balance efficiency limit. The 4th installment of the “Emerging PV reports” discusses the “PV emergence” classification with respect to the “PV technology generations” and “PV research waves” and highlights the latest device performance progress in multijunction and flexible photovoltaics. Additionally, Dale-Scarpulla's plots of efficiency-effort in terms of cumulative academic publication count are also introduced. © 2023 Wiley-VCH GmbH. |
Reus, Manuel A; Baier, Thomas; Lindenmeir, Christoph G; Weinzierl, Alexander F; Buyan-Arivjikh, Altantulga; Wegener, Simon A; Kosbahn, David P; Reb, Lennart K; Rubeck, Jan; Schwartzkopf, Matthias; Roth, Stephan V; Müller-Buschbaum, Peter Modular slot-die coater for in situ grazing-incidence x-ray scattering experiments on thin films Journal Article Review of Scientific Instruments, 95 (4), 2024, ISSN: 00346748, (Cited by: 1; All Open Access, Hybrid Gold Open Access). Abstract | Links | BibTeX | Tags: @article{Reus2024b, title = {Modular slot-die coater for in situ grazing-incidence x-ray scattering experiments on thin films}, author = {Manuel A Reus and Thomas Baier and Christoph G Lindenmeir and Alexander F Weinzierl and Altantulga Buyan-Arivjikh and Simon A Wegener and David P Kosbahn and Lennart K Reb and Jan Rubeck and Matthias Schwartzkopf and Stephan V Roth and Peter Müller-Buschbaum}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85191250978&doi=10.1063%2f5.0204673&partnerID=40&md5=2368b6fa4cd1af9516bc308d5b33c7a5}, doi = {10.1063/5.0204673}, issn = {00346748}, year = {2024}, date = {2024-01-01}, journal = {Review of Scientific Instruments}, volume = {95}, number = {4}, publisher = {American Institute of Physics}, abstract = {Multimodal in situ experiments during slot-die coating of thin films pioneer the way to kinetic studies on thin-film formation. They establish a powerful tool to understand and optimize the formation and properties of thin-film devices, e.g., solar cells, sensors, or LED films. Thin-film research benefits from time-resolved grazing-incidence wide- and small-angle x-ray scattering (GIWAXS/GISAXS) with a sub-second resolution to reveal the evolution of crystal structure, texture, and morphology during the deposition process. Simultaneously investigating optical properties by in situ photoluminescence measurements complements in-depth kinetic studies focusing on a comprehensive understanding of the triangular interdependency of processing, structure, and function for a roll-to-roll compatible, scalable thin-film deposition process. Here, we introduce a modular slot-die coater specially designed for in situ GIWAXS/GISAXS measurements and applicable to various ink systems. With a design for quick assembly, the slot-die coater permits the reproducible and comparable fabrication of thin films in the lab and at the synchrotron using the very same hardware components, as demonstrated in this work by experiments performed at Deutsches Elektronen-Synchrotron (DESY). Simultaneous to GIWAXS/GISAXS, photoluminescence measurements probe optoelectronic properties in situ during thin-film formation. An environmental chamber allows to control the atmosphere inside the coater. Modular construction and lightweight design make the coater mobile, easy to transport, quickly extendable, and adaptable to new beamline environments. © 2024 Author(s).}, note = {Cited by: 1; All Open Access, Hybrid Gold Open Access}, keywords = {}, pubstate = {published}, tppubtype = {article} } Multimodal in situ experiments during slot-die coating of thin films pioneer the way to kinetic studies on thin-film formation. They establish a powerful tool to understand and optimize the formation and properties of thin-film devices, e.g., solar cells, sensors, or LED films. Thin-film research benefits from time-resolved grazing-incidence wide- and small-angle x-ray scattering (GIWAXS/GISAXS) with a sub-second resolution to reveal the evolution of crystal structure, texture, and morphology during the deposition process. Simultaneously investigating optical properties by in situ photoluminescence measurements complements in-depth kinetic studies focusing on a comprehensive understanding of the triangular interdependency of processing, structure, and function for a roll-to-roll compatible, scalable thin-film deposition process. Here, we introduce a modular slot-die coater specially designed for in situ GIWAXS/GISAXS measurements and applicable to various ink systems. With a design for quick assembly, the slot-die coater permits the reproducible and comparable fabrication of thin films in the lab and at the synchrotron using the very same hardware components, as demonstrated in this work by experiments performed at Deutsches Elektronen-Synchrotron (DESY). Simultaneous to GIWAXS/GISAXS, photoluminescence measurements probe optoelectronic properties in situ during thin-film formation. An environmental chamber allows to control the atmosphere inside the coater. Modular construction and lightweight design make the coater mobile, easy to transport, quickly extendable, and adaptable to new beamline environments. © 2024 Author(s). |
Huang, Tzu-Yen; Brun, Anton Le P; Sochor, Benedikt; Wu, Chun-Ming; Bulut, Yusuf; Müller-Buschbaum, Peter; Roth, Stephan V; Yang, Yan-Ling Nanometer-Thick ITIC Bulk Heterojunction Films as Non-Fullerene Acceptors in Organic Solar Cells Journal Article ACS Applied Nano Materials, 7 (15), pp. 17588 – 17595, 2024, ISSN: 25740970, (Cited by: 0). Abstract | Links | BibTeX | Tags: @article{Huang202417588, title = {Nanometer-Thick ITIC Bulk Heterojunction Films as Non-Fullerene Acceptors in Organic Solar Cells}, author = {Tzu-Yen Huang and Anton P Le Brun and Benedikt Sochor and Chun-Ming Wu and Yusuf Bulut and Peter Müller-Buschbaum and Stephan V Roth and Yan-Ling Yang}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85199690359&doi=10.1021%2facsanm.4c02865&partnerID=40&md5=3a48422082eab27e5ae5e7ac9c337dcd}, doi = {10.1021/acsanm.4c02865}, issn = {25740970}, year = {2024}, date = {2024-01-01}, journal = {ACS Applied Nano Materials}, volume = {7}, number = {15}, pages = {17588 – 17595}, publisher = {American Chemical Society}, abstract = {The nanomorphology of bulk heterojunctions (BHJs) plays a critical role in determining the performance of non-fullerene organic solar cells (OSCs). Thermal annealing is commonly used to reorganize the donor and acceptor phases within the BHJs. In this study, we investigate the vertical morphology of BHJ blend films incorporating the poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3‴-di(2-octyldodecyl)-2,2′;5′,2″;5″,2‴-quaterthiophen-5,5‴-diyl)] (PffBT4T-2OD) polymer as the donor and 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′]dithiophene (ITIC) as the acceptor. Neutron reflectivity patterns and scattering length density profiles reveal that the surface of the BHJ films became diffuse when the annealing temperature was above 150 °C. We further find that mitigated agglomeration of PffBT4T-2OD side chains exhibits minimal impact on morphology post-annealing. Instead, ITIC molecules trigger aggregations, accompanied by interface diffusion and increased film roughness. X-ray scattering confirms a 5-fold increase in aggregated ITIC nanodomains after annealing. Our findings highlight that unstable ITIC phases dominate the BHJ morphology of thin films, leading to the thermal instability of OSCs. This study enhances our understanding of the BHJ morphology and offers insights into improving the performance of energy conversion devices. © 2024 American Chemical Society.}, note = {Cited by: 0}, keywords = {}, pubstate = {published}, tppubtype = {article} } The nanomorphology of bulk heterojunctions (BHJs) plays a critical role in determining the performance of non-fullerene organic solar cells (OSCs). Thermal annealing is commonly used to reorganize the donor and acceptor phases within the BHJs. In this study, we investigate the vertical morphology of BHJ blend films incorporating the poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3‴-di(2-octyldodecyl)-2,2′;5′,2″;5″,2‴-quaterthiophen-5,5‴-diyl)] (PffBT4T-2OD) polymer as the donor and 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′]dithiophene (ITIC) as the acceptor. Neutron reflectivity patterns and scattering length density profiles reveal that the surface of the BHJ films became diffuse when the annealing temperature was above 150 °C. We further find that mitigated agglomeration of PffBT4T-2OD side chains exhibits minimal impact on morphology post-annealing. Instead, ITIC molecules trigger aggregations, accompanied by interface diffusion and increased film roughness. X-ray scattering confirms a 5-fold increase in aggregated ITIC nanodomains after annealing. Our findings highlight that unstable ITIC phases dominate the BHJ morphology of thin films, leading to the thermal instability of OSCs. This study enhances our understanding of the BHJ morphology and offers insights into improving the performance of energy conversion devices. © 2024 American Chemical Society. |
Maier, Thomas L; de Kam, Lucas B T; Golibrzuch, Matthias; Angerer, Tina; Becherer, Markus; Krischer, Katharina How Metal/Insulator Interfaces Enable an Enhancement of the Hydrogen Evolution Reaction Kinetics Journal Article ChemElectroChem, 11 (11), 2024, ISSN: 21960216, (Cited by: 0; All Open Access, Gold Open Access). Abstract | Links | BibTeX | Tags: @article{Maier2024, title = {How Metal/Insulator Interfaces Enable an Enhancement of the Hydrogen Evolution Reaction Kinetics}, author = {Thomas L Maier and Lucas B T. de Kam and Matthias Golibrzuch and Tina Angerer and Markus Becherer and Katharina Krischer}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85193040302&doi=10.1002%2fcelc.202400109&partnerID=40&md5=fd23b3506d9f1ab0592cb211f1de3759}, doi = {10.1002/celc.202400109}, issn = {21960216}, year = {2024}, date = {2024-01-01}, journal = {ChemElectroChem}, volume = {11}, number = {11}, publisher = {John Wiley and Sons Inc}, abstract = {The nanostructuring of electrodes is a common way of increasing electrocatalytic activity. Yet, the fact that the presence of insulating material in nanostructured composites can have a positive effect on efficiency was an unexpected recent finding. The rate enhancement has been linked to different electric fields at the insulator and metal interfaces, facilitating enhanced transport of reaction products into the bulk electrolyte. In this article, we further uncover the origin of the rate enhancement with parameter studies and simulations. We experimentally investigate various parameter dependencies of the alkaline Hydrogen Evolution Reaction (HER) on well-defined nanometer-sized Au arrays embedded in a silicon nitride insulating layer. We find a significant enhancement of the HER for all experimental conditions and opposite activity trends with pH, electrolyte concentration and the cationic species compared to a continuous Au electrode. Using a mean field model, we quantify the electrostatic interfacial pressure above the Au and the insulator patches. Combining the double layer simulations with rate equations, we demonstrate that all parameter variations can be consistently explained by the fact that the double layer structure above the insulator patches is much less rigid than above the metal islands and is independent of the applied potential. © 2024 The Authors. ChemElectroChem published by Wiley-VCH GmbH.}, note = {Cited by: 0; All Open Access, Gold Open Access}, keywords = {}, pubstate = {published}, tppubtype = {article} } The nanostructuring of electrodes is a common way of increasing electrocatalytic activity. Yet, the fact that the presence of insulating material in nanostructured composites can have a positive effect on efficiency was an unexpected recent finding. The rate enhancement has been linked to different electric fields at the insulator and metal interfaces, facilitating enhanced transport of reaction products into the bulk electrolyte. In this article, we further uncover the origin of the rate enhancement with parameter studies and simulations. We experimentally investigate various parameter dependencies of the alkaline Hydrogen Evolution Reaction (HER) on well-defined nanometer-sized Au arrays embedded in a silicon nitride insulating layer. We find a significant enhancement of the HER for all experimental conditions and opposite activity trends with pH, electrolyte concentration and the cationic species compared to a continuous Au electrode. Using a mean field model, we quantify the electrostatic interfacial pressure above the Au and the insulator patches. Combining the double layer simulations with rate equations, we demonstrate that all parameter variations can be consistently explained by the fact that the double layer structure above the insulator patches is much less rigid than above the metal islands and is independent of the applied potential. © 2024 The Authors. ChemElectroChem published by Wiley-VCH GmbH. |
Rasouli, Azam; Kudyba, Artur; Bruzda, Grzegorz; Safarian, Jafar; Tranell, Gabriella High-Temperature Reactive Wetting of Natural Quartz by Liquid Magnesium Journal Article Materials, 17 (6), 2024, ISSN: 19961944, (Cited by: 0; All Open Access, Gold Open Access). Abstract | Links | BibTeX | Tags: @article{Rasouli2024, title = {High-Temperature Reactive Wetting of Natural Quartz by Liquid Magnesium}, author = {Azam Rasouli and Artur Kudyba and Grzegorz Bruzda and Jafar Safarian and Gabriella Tranell}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85189066882&doi=10.3390%2fma17061302&partnerID=40&md5=9c63350502cd6144c155f86b3c7474f5}, doi = {10.3390/ma17061302}, issn = {19961944}, year = {2024}, date = {2024-01-01}, journal = {Materials}, volume = {17}, number = {6}, publisher = {Multidisciplinary Digital Publishing Institute (MDPI)}, abstract = {High-temperature wetting of natural, high-purity quartz (SiO2) and liquid magnesium (Mg) was investigated at temperatures between 973 and 1273 K. Sessile drop experiments using the capillary purification (CP) procedure were carried out under an Ar gas atmosphere (N6.0), eliminating the native oxide layer on the surface of Mg melt. The results showed that the wetting behavior was strongly dependent on temperature. At 973 and 1073 K, the wetting system displayed relatively large contact angles of 90° and 65°, respectively, demonstrating modest wetting. The wetting increased to some extent by increasing the temperature to 1123 K with a wetting angle of 22°. However, the SiO2/Mg system demonstrated complete wetting at temperatures of 1173 K and above. Furthermore, interface microstructure examination showed different reaction product phases/microstructures, depending on the wetting experiment temperature. © 2024 by the authors.}, note = {Cited by: 0; All Open Access, Gold Open Access}, keywords = {}, pubstate = {published}, tppubtype = {article} } High-temperature wetting of natural, high-purity quartz (SiO2) and liquid magnesium (Mg) was investigated at temperatures between 973 and 1273 K. Sessile drop experiments using the capillary purification (CP) procedure were carried out under an Ar gas atmosphere (N6.0), eliminating the native oxide layer on the surface of Mg melt. The results showed that the wetting behavior was strongly dependent on temperature. At 973 and 1073 K, the wetting system displayed relatively large contact angles of 90° and 65°, respectively, demonstrating modest wetting. The wetting increased to some extent by increasing the temperature to 1123 K with a wetting angle of 22°. However, the SiO2/Mg system demonstrated complete wetting at temperatures of 1173 K and above. Furthermore, interface microstructure examination showed different reaction product phases/microstructures, depending on the wetting experiment temperature. © 2024 by the authors. |
Tian, Ting; Tu, Suo; Xu, Ang; Yin, Shanshan; Oechsle, Anna Lena; Xiao, Tianxiao; Vagias, Apostolos; Eichhorn, Johanna; Suo, Jinping; Yang, Zhangcan; Bernstorff, Sigrid; Müller-Buschbaum, Peter Unraveling the Morphology-Function Correlation of Mesoporous ZnO Films upon Water Exposure Journal Article Advanced Functional Materials, 34 (8), 2024, ISSN: 1616301X, (Cited by: 1; All Open Access, Hybrid Gold Open Access). Abstract | Links | BibTeX | Tags: @article{Tian2024, title = {Unraveling the Morphology-Function Correlation of Mesoporous ZnO Films upon Water Exposure}, author = {Ting Tian and Suo Tu and Ang Xu and Shanshan Yin and Anna Lena Oechsle and Tianxiao Xiao and Apostolos Vagias and Johanna Eichhorn and Jinping Suo and Zhangcan Yang and Sigrid Bernstorff and Peter Müller-Buschbaum}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85175527704&doi=10.1002%2fadfm.202311793&partnerID=40&md5=c31a4f3b28afc46702547814c531584e}, doi = {10.1002/adfm.202311793}, issn = {1616301X}, year = {2024}, date = {2024-01-01}, journal = {Advanced Functional Materials}, volume = {34}, number = {8}, publisher = {John Wiley and Sons Inc}, abstract = {Ubiquitous moisture in synthetic conditions and ambient environments can strongly influence the conductivity of ZnO semiconductors via the chemisorption and physisorption of water molecules on the ZnO surface. Such an intrinsically water-sensitive nature will become more evident in mesoporous ZnO films where a large surface area and active sites are created simultaneously. However, fundamental insights underlying water-mediated ZnO surface chemistry and electrical conductivity and the factors affecting them remain ambiguous due to the complexity of ZnO surfaces and the difficulties of in situ characterizations at multi-dimensions. Here, self-assembling diblock copolymers are exploited as structure-directing agents to achieve mesoporous ZnO thin films with highly tailorable structural characteristics ranging from nanomorphologies, over crystalline levels, to defect contents. As verified by theoretical calculations, the presence of oxygen vacancy will facilitate favorable water adsorption and subsequent dissociation on the polar ZnO surfaces. Upon humidity exposure with progressively increased levels, mesoporous ZnO films are revealed to follow an almost positive relationship between adsorption and electrical conductivity but show superior morphological stability. This work not only elucidates the water-governed ZnO surface chemistry but may also promote a comprehensive understanding of the morphology-function relationship on ZnO-based electronics. © 2023 The Authors. Advanced Functional Materials published by Wiley-VCH GmbH.}, note = {Cited by: 1; All Open Access, Hybrid Gold Open Access}, keywords = {}, pubstate = {published}, tppubtype = {article} } Ubiquitous moisture in synthetic conditions and ambient environments can strongly influence the conductivity of ZnO semiconductors via the chemisorption and physisorption of water molecules on the ZnO surface. Such an intrinsically water-sensitive nature will become more evident in mesoporous ZnO films where a large surface area and active sites are created simultaneously. However, fundamental insights underlying water-mediated ZnO surface chemistry and electrical conductivity and the factors affecting them remain ambiguous due to the complexity of ZnO surfaces and the difficulties of in situ characterizations at multi-dimensions. Here, self-assembling diblock copolymers are exploited as structure-directing agents to achieve mesoporous ZnO thin films with highly tailorable structural characteristics ranging from nanomorphologies, over crystalline levels, to defect contents. As verified by theoretical calculations, the presence of oxygen vacancy will facilitate favorable water adsorption and subsequent dissociation on the polar ZnO surfaces. Upon humidity exposure with progressively increased levels, mesoporous ZnO films are revealed to follow an almost positive relationship between adsorption and electrical conductivity but show superior morphological stability. This work not only elucidates the water-governed ZnO surface chemistry but may also promote a comprehensive understanding of the morphology-function relationship on ZnO-based electronics. © 2023 The Authors. Advanced Functional Materials published by Wiley-VCH GmbH. |
Kumar, Labeesh; Nandan, Bhanu; Sarkar, Swagato; König, Tobias A F; Pohl, Darius; Tsuda, Takuya; Zainuddin, Muhammad S B; Humenik, Martin; Scheibel, Thomas; Horechyy, Andriy Enhanced photocatalytic performance of coaxially electrospun titania nanofibers comprising yolk-shell particles Journal Article Journal of Colloid and Interface Science, 674 , pp. 560 – 575, 2024, ISSN: 00219797, (Cited by: 1; All Open Access, Hybrid Gold Open Access). Abstract | Links | BibTeX | Tags: @article{Kumar2024560, title = {Enhanced photocatalytic performance of coaxially electrospun titania nanofibers comprising yolk-shell particles}, author = {Labeesh Kumar and Bhanu Nandan and Swagato Sarkar and Tobias A F König and Darius Pohl and Takuya Tsuda and Muhammad S B Zainuddin and Martin Humenik and Thomas Scheibel and Andriy Horechyy}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85197361436&doi=10.1016%2fj.jcis.2024.06.133&partnerID=40&md5=80e88d019a726da6fa5ed4a36d48cc7f}, doi = {10.1016/j.jcis.2024.06.133}, issn = {00219797}, year = {2024}, date = {2024-01-01}, journal = {Journal of Colloid and Interface Science}, volume = {674}, pages = {560 – 575}, publisher = {Academic Press Inc.}, abstract = {The present paper reports the fabrication of novel types of hybrid fibrous photocatalysts by combining block copolymer (BCP) templating, sol–gel processing, and coaxial electrospinning techniques. Coaxial electrospinning produces core–shell nanofibers (NFs), which are converted into hollow porous TiO2 NFs using an oxidative calcination step. Hybrid BCP micelles comprising a single plasmonic nanoparticle (NP) in their core and thereof derived silica-coated core–shell particles are utilized as precursors to generate yolk-shell type particulate inclusions in photocatalytically active NFs. The catalytic and photocatalytic activity of calcined NFs comprising different types of yolk-shell particles is systematically investigated and compared. Interestingly, calcined NFs comprising silica-coated yolk-shells demonstrate enhanced catalytic and photocatalytic performance despite the presence of silica shell separating plasmonic NP from the TiO2 matrix. Electromagnetic simulations indicate that this enhancement is caused by a localized surface plasmon resonance and a confinement effect in silica-coated yolk-shells embedded in porous TiO2 NFs. Utilization of the coaxially electrospun TiO2 NFs in combination with yolk-shells comprising plasmonic NPs reveals to be a potent method for the photocatalytic decomposition of numerous pollutants. It is worth noting that this study stands as the first occurrence of combining yolk-shells (Au@void@SiO2) with porous electrospun NFs (TiO2) for photocatalytic purposes and gaining an understanding of plasmon and confinement effects for photocatalytic performance. This approach represents a promising route for fabricating highly active and up-scalable fibrous photocatalytic systems. © 2024 The Authors}, note = {Cited by: 1; All Open Access, Hybrid Gold Open Access}, keywords = {}, pubstate = {published}, tppubtype = {article} } The present paper reports the fabrication of novel types of hybrid fibrous photocatalysts by combining block copolymer (BCP) templating, sol–gel processing, and coaxial electrospinning techniques. Coaxial electrospinning produces core–shell nanofibers (NFs), which are converted into hollow porous TiO2 NFs using an oxidative calcination step. Hybrid BCP micelles comprising a single plasmonic nanoparticle (NP) in their core and thereof derived silica-coated core–shell particles are utilized as precursors to generate yolk-shell type particulate inclusions in photocatalytically active NFs. The catalytic and photocatalytic activity of calcined NFs comprising different types of yolk-shell particles is systematically investigated and compared. Interestingly, calcined NFs comprising silica-coated yolk-shells demonstrate enhanced catalytic and photocatalytic performance despite the presence of silica shell separating plasmonic NP from the TiO2 matrix. Electromagnetic simulations indicate that this enhancement is caused by a localized surface plasmon resonance and a confinement effect in silica-coated yolk-shells embedded in porous TiO2 NFs. Utilization of the coaxially electrospun TiO2 NFs in combination with yolk-shells comprising plasmonic NPs reveals to be a potent method for the photocatalytic decomposition of numerous pollutants. It is worth noting that this study stands as the first occurrence of combining yolk-shells (Au@void@SiO2) with porous electrospun NFs (TiO2) for photocatalytic purposes and gaining an understanding of plasmon and confinement effects for photocatalytic performance. This approach represents a promising route for fabricating highly active and up-scalable fibrous photocatalytic systems. © 2024 The Authors |
Xiao, Tianxiao; Tu, Suo; Tian, Ting; Chen, Wei; Cao, Wei; Liang, Suzhe; Guo, Renjun; Liu, Liangzhen; Li, Yanan; Guan, Tianfu; Liu, Haochen; Wang, Kai; Schwartzkopf, Matthias; Fischer, Roland A; Roth, Stephan V; Müller-Buschbaum, Peter Autonomous self-healing hybrid energy harvester based on the combination of triboelectric nanogenerator and quantum dot solar cell Journal Article Nano Energy, 125 , 2024, ISSN: 22112855, (Cited by: 3; All Open Access, Hybrid Gold Open Access). Abstract | Links | BibTeX | Tags: @article{Xiao2024b, title = {Autonomous self-healing hybrid energy harvester based on the combination of triboelectric nanogenerator and quantum dot solar cell}, author = {Tianxiao Xiao and Suo Tu and Ting Tian and Wei Chen and Wei Cao and Suzhe Liang and Renjun Guo and Liangzhen Liu and Yanan Li and Tianfu Guan and Haochen Liu and Kai Wang and Matthias Schwartzkopf and Roland A Fischer and Stephan V Roth and Peter Müller-Buschbaum}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85189558263&doi=10.1016%2fj.nanoen.2024.109555&partnerID=40&md5=fe94f06e4335e9dfe56b1d138c4a15ec}, doi = {10.1016/j.nanoen.2024.109555}, issn = {22112855}, year = {2024}, date = {2024-01-01}, journal = {Nano Energy}, volume = {125}, publisher = {Elsevier Ltd}, abstract = {Realization of multi-source energy harvesting with one single device would maximize power output. Thus, it is emerging as a promising strategy towards renewable energy generation and has attracted worldwide attention in the past decades. Capable of capturing mechanical energy that is ubiquitous in the ambient environment, triboelectric nanogenerator (TENG) has been considered a novel yet effective source towards next-generation energy harvesting. In this work, a flexible hybrid energy harvester (HEH) is developed via the rational integration of autonomous self-healing TENG and high bending-stable lead sulfide quantum dot (PbS QD) solar cell, enabling independent electricity generation by two different mechanisms. The single-electrode mode TENG component with self-healing is realized by a polydimethylsiloxane/Triton X-100 (PDMS/TX100) mixture as the dielectric layer and the shared gold (Au) electrode, which generates 0.39 µA of output current (Iout), 24.6 V of output voltages (Vout), 15.4 nC of transfer charges (Qsc), and 7.80 mW m−2 of output power peak density. The thin-film solar cell component is based on a PbS QD layer as the light absorber with a planar structure fabricated under low-cost and compatible conditions, achieving 22.8 mA cm−2 of short-circuit current density (Jsc) and 4.92% of power conversion efficiency (PCE). As a proof of concept, an electronic watch is successfully powered by harnessing ambient mechanical and solar energy with a hybridized energy cell. This approach will offer more opportunities to construct a versatile platform towards remote monitoring and smart home systems. © 2024 The Authors}, note = {Cited by: 3; All Open Access, Hybrid Gold Open Access}, keywords = {}, pubstate = {published}, tppubtype = {article} } Realization of multi-source energy harvesting with one single device would maximize power output. Thus, it is emerging as a promising strategy towards renewable energy generation and has attracted worldwide attention in the past decades. Capable of capturing mechanical energy that is ubiquitous in the ambient environment, triboelectric nanogenerator (TENG) has been considered a novel yet effective source towards next-generation energy harvesting. In this work, a flexible hybrid energy harvester (HEH) is developed via the rational integration of autonomous self-healing TENG and high bending-stable lead sulfide quantum dot (PbS QD) solar cell, enabling independent electricity generation by two different mechanisms. The single-electrode mode TENG component with self-healing is realized by a polydimethylsiloxane/Triton X-100 (PDMS/TX100) mixture as the dielectric layer and the shared gold (Au) electrode, which generates 0.39 µA of output current (Iout), 24.6 V of output voltages (Vout), 15.4 nC of transfer charges (Qsc), and 7.80 mW m−2 of output power peak density. The thin-film solar cell component is based on a PbS QD layer as the light absorber with a planar structure fabricated under low-cost and compatible conditions, achieving 22.8 mA cm−2 of short-circuit current density (Jsc) and 4.92% of power conversion efficiency (PCE). As a proof of concept, an electronic watch is successfully powered by harnessing ambient mechanical and solar energy with a hybridized energy cell. This approach will offer more opportunities to construct a versatile platform towards remote monitoring and smart home systems. © 2024 The Authors |
Tu, Suo; Tian, Ting; Xiao, Tianxiao; Yao, Xiangtong; Shen, Sicong; Wu, Yansong; Liu, Yinlong; Bing, Zhenshan; Huang, Kai; Knoll, Alois; Yin, Shanshan; Liang, Suzhe; Heger, Julian E; Pan, Guangjiu; Schwartzkopf, Matthias; Roth, Stephan V; Müller-Buschbaum, Peter Humidity Stable Thermoelectric Hybrid Materials Toward a Self-Powered Triple Sensing System Journal Article Advanced Functional Materials, 34 (25), 2024, ISSN: 1616301X, (Cited by: 4; All Open Access, Hybrid Gold Open Access). Abstract | Links | BibTeX | Tags: @article{Tu2024, title = {Humidity Stable Thermoelectric Hybrid Materials Toward a Self-Powered Triple Sensing System}, author = {Suo Tu and Ting Tian and Tianxiao Xiao and Xiangtong Yao and Sicong Shen and Yansong Wu and Yinlong Liu and Zhenshan Bing and Kai Huang and Alois Knoll and Shanshan Yin and Suzhe Liang and Julian E Heger and Guangjiu Pan and Matthias Schwartzkopf and Stephan V Roth and Peter Müller-Buschbaum}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85184738841&doi=10.1002%2fadfm.202316088&partnerID=40&md5=287dd8d98d9b38231d5a939bd31c8f2c}, doi = {10.1002/adfm.202316088}, issn = {1616301X}, year = {2024}, date = {2024-01-01}, journal = {Advanced Functional Materials}, volume = {34}, number = {25}, publisher = {John Wiley and Sons Inc}, abstract = {Highly sensitive and humidity-resistive detection of the most common physical stimuli is of primary importance for practical application in real-time monitoring. Here, a simple yet effective strategy is reported to achieve a highly humidity-stable hybrid composite that enables simultaneous and accurate pressure and temperature sensing in a single sensor. The improved electronic performance is due to the enhanced planarity of poly (3,-4ethylenedioxythiophene) (PEDOT) and charge transfer between PEDOT:polystyrene sulfonate (PEDOT:PSS) and multi-walled carbon nanotubes (CNTs) by strong π–π interaction. The preferred electronic pathway induced by a robust morphology in the hybrid composite is responsible for the high humidity stability. This study also demonstrates that the sensor has tremendous potential for intelligent object identification with a high level of 97.78% accuracy. Together with the position-detection capability of a triboelectric nanogenerator (TENG), advantages for potential industrial applications of the triple sensing system in terms of intelligent classification without seeing are foreseen. © 2024 The Authors. Advanced Functional Materials published by Wiley-VCH GmbH.}, note = {Cited by: 4; All Open Access, Hybrid Gold Open Access}, keywords = {}, pubstate = {published}, tppubtype = {article} } Highly sensitive and humidity-resistive detection of the most common physical stimuli is of primary importance for practical application in real-time monitoring. Here, a simple yet effective strategy is reported to achieve a highly humidity-stable hybrid composite that enables simultaneous and accurate pressure and temperature sensing in a single sensor. The improved electronic performance is due to the enhanced planarity of poly (3,-4ethylenedioxythiophene) (PEDOT) and charge transfer between PEDOT:polystyrene sulfonate (PEDOT:PSS) and multi-walled carbon nanotubes (CNTs) by strong π–π interaction. The preferred electronic pathway induced by a robust morphology in the hybrid composite is responsible for the high humidity stability. This study also demonstrates that the sensor has tremendous potential for intelligent object identification with a high level of 97.78% accuracy. Together with the position-detection capability of a triboelectric nanogenerator (TENG), advantages for potential industrial applications of the triple sensing system in terms of intelligent classification without seeing are foreseen. © 2024 The Authors. Advanced Functional Materials published by Wiley-VCH GmbH. |
Hegner, Franziska S; Cohen, Adi; Rudel, Stefan S; Kronawitter, Silva M; Grumet, Manuel; Zhu, Xiangzhou; Korobko, Roman; Houben, Lothar; Jiang, Chang-Ming; Schnick, Wolfgang; Kieslich, Gregor; Yaffe, Omer; Sharp, Ian D; Egger, David A The Critical Role of Anharmonic Lattice Dynamics for Macroscopic Properties of the Visible Light Absorbing Nitride Semiconductor CuTaN2 Journal Article Advanced Energy Materials, 14 (19), 2024, ISSN: 16146832, (Cited by: 1; All Open Access, Hybrid Gold Open Access). Abstract | Links | BibTeX | Tags: @article{Hegner2024, title = {The Critical Role of Anharmonic Lattice Dynamics for Macroscopic Properties of the Visible Light Absorbing Nitride Semiconductor CuTaN2}, author = {Franziska S Hegner and Adi Cohen and Stefan S Rudel and Silva M Kronawitter and Manuel Grumet and Xiangzhou Zhu and Roman Korobko and Lothar Houben and Chang-Ming Jiang and Wolfgang Schnick and Gregor Kieslich and Omer Yaffe and Ian D Sharp and David A Egger}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85188909385&doi=10.1002%2faenm.202303059&partnerID=40&md5=8d45614f8e878ca4ff40bda022a028f0}, doi = {10.1002/aenm.202303059}, issn = {16146832}, year = {2024}, date = {2024-01-01}, journal = {Advanced Energy Materials}, volume = {14}, number = {19}, publisher = {John Wiley and Sons Inc}, abstract = {Ternary nitride semiconductors are rapidly emerging as a promising class of materials for energy conversion applications, offering an appealing combination of strong light absorption in the visible range, desirable charge transport characteristics, and good chemical stability. In this work, it is shown that finite-temperature lattice dynamics in CuTaN2 – a prototypical ternary nitride displaying particularly strong visible light absorption – exhibit a pronounced anharmonic character that plays an essential role in defining its macroscopic optoelectronic and thermal properties. Low-frequency vibrational modes that are Raman-inactive from symmetry considerations of the average crystal structure and unstable in harmonic phonon calculations are found to appear as intensive Raman features near room temperature. The atomic contributions to the anharmonic vibrations are characterized by combining Raman measurements with molecular dynamics and density functional theory calculations. This analysis reveals that anharmonic lattice dynamics have large ramifications on the fundamental properties of this compound, resulting in uniaxial negative thermal expansion and the opening of its bandgap to a near-optimal value for solar energy harvesting. The atomic-level understanding of anharmonic lattice dynamics, as well as the finding that they strongly influence key properties of this semiconductor at room temperature, have important implications for design of new functional materials, especially within the emerging class of ternary nitride semiconductors. © 2024 The Authors. Advanced Energy Materials published by Wiley-VCH GmbH.}, note = {Cited by: 1; All Open Access, Hybrid Gold Open Access}, keywords = {}, pubstate = {published}, tppubtype = {article} } Ternary nitride semiconductors are rapidly emerging as a promising class of materials for energy conversion applications, offering an appealing combination of strong light absorption in the visible range, desirable charge transport characteristics, and good chemical stability. In this work, it is shown that finite-temperature lattice dynamics in CuTaN2 – a prototypical ternary nitride displaying particularly strong visible light absorption – exhibit a pronounced anharmonic character that plays an essential role in defining its macroscopic optoelectronic and thermal properties. Low-frequency vibrational modes that are Raman-inactive from symmetry considerations of the average crystal structure and unstable in harmonic phonon calculations are found to appear as intensive Raman features near room temperature. The atomic contributions to the anharmonic vibrations are characterized by combining Raman measurements with molecular dynamics and density functional theory calculations. This analysis reveals that anharmonic lattice dynamics have large ramifications on the fundamental properties of this compound, resulting in uniaxial negative thermal expansion and the opening of its bandgap to a near-optimal value for solar energy harvesting. The atomic-level understanding of anharmonic lattice dynamics, as well as the finding that they strongly influence key properties of this semiconductor at room temperature, have important implications for design of new functional materials, especially within the emerging class of ternary nitride semiconductors. © 2024 The Authors. Advanced Energy Materials published by Wiley-VCH GmbH. |
Posnjak, Gregor; Yin, Xin; Butler, Paul; Bienek, Oliver; Dass, Mihir; Lee, Seungwoo; Sharp, Ian D; Liedl, Tim Diamond-lattice photonic crystals assembled from DNA origami Journal Article Science, 384 (6697), pp. 781 – 785, 2024, ISSN: 00368075, (Cited by: 6; All Open Access, Green Open Access). Abstract | Links | BibTeX | Tags: @article{Posnjak2024781, title = {Diamond-lattice photonic crystals assembled from DNA origami}, author = {Gregor Posnjak and Xin Yin and Paul Butler and Oliver Bienek and Mihir Dass and Seungwoo Lee and Ian D Sharp and Tim Liedl}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85193516157&doi=10.1126%2fscience.adl2733&partnerID=40&md5=6d4f8061bc1a63794487b181922a88ed}, doi = {10.1126/science.adl2733}, issn = {00368075}, year = {2024}, date = {2024-01-01}, journal = {Science}, volume = {384}, number = {6697}, pages = {781 – 785}, publisher = {American Association for the Advancement of Science}, abstract = {Colloidal self-assembly allows rational design of structures on the micrometer and submicrometer scale. One architecture that can generate complete three-dimensional photonic bandgaps is the diamond cubic lattice, which has remained difficult to realize at length scales comparable with the wavelength of visible or ultraviolet light. In this work, we demonstrate three-dimensional photonic crystals self-assembled from DNA origami that act as precisely programmable patchy colloids. Our DNA-based nanoscale tetrapods crystallize into a rod-connected diamond cubic lattice with a periodicity of 170 nanometers. This structure serves as a scaffold for atomic-layer deposition of high–refractive index materials such as titanium dioxide, yielding a tunable photonic bandgap in the near-ultraviolet. © 2024 American Association for the Advancement of Science. All rights reserved.}, note = {Cited by: 6; All Open Access, Green Open Access}, keywords = {}, pubstate = {published}, tppubtype = {article} } Colloidal self-assembly allows rational design of structures on the micrometer and submicrometer scale. One architecture that can generate complete three-dimensional photonic bandgaps is the diamond cubic lattice, which has remained difficult to realize at length scales comparable with the wavelength of visible or ultraviolet light. In this work, we demonstrate three-dimensional photonic crystals self-assembled from DNA origami that act as precisely programmable patchy colloids. Our DNA-based nanoscale tetrapods crystallize into a rod-connected diamond cubic lattice with a periodicity of 170 nanometers. This structure serves as a scaffold for atomic-layer deposition of high–refractive index materials such as titanium dioxide, yielding a tunable photonic bandgap in the near-ultraviolet. © 2024 American Association for the Advancement of Science. All rights reserved. |
Mentzel, Paul; Holzapfel, Marco; Schmiedel, Alexander; Günther, Johanna; Michel, Maximilian; Krummenacher, Ivo; Wodyński, Artur; Kaupp, Martin; Braunschweig, Holger; Lambert, Christoph Structure and Photophysics of N-Tolanyl-phenochalcogenazines and their Radical Cations Journal Article Chemistry - A European Journal, 30 (19), 2024, ISSN: 09476539, (Cited by: 0; All Open Access, Hybrid Gold Open Access). Abstract | Links | BibTeX | Tags: @article{Mentzel2024, title = {Structure and Photophysics of N-Tolanyl-phenochalcogenazines and their Radical Cations}, author = {Paul Mentzel and Marco Holzapfel and Alexander Schmiedel and Johanna Günther and Maximilian Michel and Ivo Krummenacher and Artur Wodyński and Martin Kaupp and Holger Braunschweig and Christoph Lambert}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85185108520&doi=10.1002%2fchem.202303782&partnerID=40&md5=b86f6d73ed4a41c13fbe919d29156c99}, doi = {10.1002/chem.202303782}, issn = {09476539}, year = {2024}, date = {2024-01-01}, journal = {Chemistry - A European Journal}, volume = {30}, number = {19}, publisher = {John Wiley and Sons Inc}, abstract = {The study focuses on the structural and photophysical characteristics of neutral and oxidized forms of N-tolanyl-phenochalcogenazines PZX-tolan with X=O, S, Se, and Te. X-ray crystal structure analyses show a pseudo-equatorial (pe) structure of the tolan substituent in the O, S, and Se dyads, while the Te dyad possesses a pseudo-axial (pa) structure. DFT calculations suggest the pe structure for O and S, and the pa structure for Se and Te as stable forms. Steady-state and femtosecond-time resolved optical spectroscopy in toluene solution indicate that the O and S dyads emit from a CT state, whereas the Se and Te dyads emit from a tolan-localized state. The T1 state is tolan-localized in all cases, showing phosphorescence at 77 K. The heavy atom effect of chalcogens induces intersystem crossing from S1 to Tx, resulting in a decreasing S1 lifetime from 2.1 ns to 0.42 ps. The T1 states possess potential for singlet oxygen sensitization with a high quantum yield (ca. 40 %) for the O, S, and Se dyads. Radical cations exhibit spin density primarily localized at the heterocycle. EPR measurements and quasirelativistic DFT calculations reveal a very strong g-tensor anisotropy, supporting the pe structure for the S and Se derivatives. © 2024 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.}, note = {Cited by: 0; All Open Access, Hybrid Gold Open Access}, keywords = {}, pubstate = {published}, tppubtype = {article} } The study focuses on the structural and photophysical characteristics of neutral and oxidized forms of N-tolanyl-phenochalcogenazines PZX-tolan with X=O, S, Se, and Te. X-ray crystal structure analyses show a pseudo-equatorial (pe) structure of the tolan substituent in the O, S, and Se dyads, while the Te dyad possesses a pseudo-axial (pa) structure. DFT calculations suggest the pe structure for O and S, and the pa structure for Se and Te as stable forms. Steady-state and femtosecond-time resolved optical spectroscopy in toluene solution indicate that the O and S dyads emit from a CT state, whereas the Se and Te dyads emit from a tolan-localized state. The T1 state is tolan-localized in all cases, showing phosphorescence at 77 K. The heavy atom effect of chalcogens induces intersystem crossing from S1 to Tx, resulting in a decreasing S1 lifetime from 2.1 ns to 0.42 ps. The T1 states possess potential for singlet oxygen sensitization with a high quantum yield (ca. 40 %) for the O, S, and Se dyads. Radical cations exhibit spin density primarily localized at the heterocycle. EPR measurements and quasirelativistic DFT calculations reveal a very strong g-tensor anisotropy, supporting the pe structure for the S and Se derivatives. © 2024 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH. |
de Kam, Lucas B T; Maier, Thomas L; Krischer, Katharina Electrolyte effects on the alkaline hydrogen evolution reaction: A mean-field approach Journal Article Electrochimica Acta, 497 , 2024, ISSN: 00134686, (Cited by: 0; All Open Access, Hybrid Gold Open Access). Abstract | Links | BibTeX | Tags: @article{deKam2024, title = {Electrolyte effects on the alkaline hydrogen evolution reaction: A mean-field approach}, author = {Lucas B T de Kam and Thomas L Maier and Katharina Krischer}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85195863948&doi=10.1016%2fj.electacta.2024.144530&partnerID=40&md5=568a9ec1f88599475525bd6d1a5f6cee}, doi = {10.1016/j.electacta.2024.144530}, issn = {00134686}, year = {2024}, date = {2024-01-01}, journal = {Electrochimica Acta}, volume = {497}, publisher = {Elsevier Ltd}, abstract = {This paper introduces the combination of an advanced double-layer model with electrochemical kinetics to explain electrolyte effects on the alkaline hydrogen evolution reaction. It is known from experimental studies that the alkaline hydrogen evolution current shows a strong dependence on the concentration and identity of cations in the electrolyte, but is independent of pH. To explain these effects, we formulate the faradaic current in terms of the electric potential in the double layer, which is calculated using a mean-field model that takes into account the cation and anion sizes as well as the electric dipole moment of water molecules. We propose that the Volmer step consists of two activated processes: a water reduction sub-step, and a sub-step in which OH− is transferred away from the reaction plane through the double layer. Either of these sub-steps may limit the rate. The proposed models for these sub-steps qualitatively explain experimental observations, including cation effects, pH-independence, and the trend reversal between gold and platinum electrodes. We also assess the quantitative accuracy of the water-reduction-limited current model; we suggest that the predicted functional relationship is valid as long as the hydrogen bonding structure of water near the electrode is sufficiently maintained. © 2024 The Author(s)}, note = {Cited by: 0; All Open Access, Hybrid Gold Open Access}, keywords = {}, pubstate = {published}, tppubtype = {article} } This paper introduces the combination of an advanced double-layer model with electrochemical kinetics to explain electrolyte effects on the alkaline hydrogen evolution reaction. It is known from experimental studies that the alkaline hydrogen evolution current shows a strong dependence on the concentration and identity of cations in the electrolyte, but is independent of pH. To explain these effects, we formulate the faradaic current in terms of the electric potential in the double layer, which is calculated using a mean-field model that takes into account the cation and anion sizes as well as the electric dipole moment of water molecules. We propose that the Volmer step consists of two activated processes: a water reduction sub-step, and a sub-step in which OH− is transferred away from the reaction plane through the double layer. Either of these sub-steps may limit the rate. The proposed models for these sub-steps qualitatively explain experimental observations, including cation effects, pH-independence, and the trend reversal between gold and platinum electrodes. We also assess the quantitative accuracy of the water-reduction-limited current model; we suggest that the predicted functional relationship is valid as long as the hydrogen bonding structure of water near the electrode is sufficiently maintained. © 2024 The Author(s) |