1208.
L Bäuml, R De Vivie-Riedle
Coupled Nuclear and Electron Dynamics in Chlorophyll Unraveled by XMS-CASPT2 X-ray Absorption Spectra Journal Article
In: The Journal of Physical Chemistry B, vol. 129, no. 8, pp. 2159-2167, 2025, ISSN: 1520-6106.
@article{nokey,
title = {Coupled Nuclear and Electron Dynamics in Chlorophyll Unraveled by XMS-CASPT2 X-ray Absorption Spectra},
author = {L B\"{a}uml and R De Vivie-Riedle},
url = {https://doi.org/10.1021/acs.jpcb.4c07787},
doi = {10.1021/acs.jpcb.4c07787},
issn = {1520-6106},
year = {2025},
date = {2025-02-27},
journal = {The Journal of Physical Chemistry B},
volume = {129},
number = {8},
pages = {2159-2167},
abstract = {Attosecond spectroscopy, especially time-resolved X-ray absorption spectra (XAS), enables direct observation of ultrafast molecular dynamics. The complementary and even preceding development of theoretical simulations can offer the necessary guidance and stimulate new experiments. In this work, we simulated high-level XAS for the magnesium and nitrogen K-edge of chlorophyll a. In our previous work on the ultrafast relaxation process in the Q-band, our quantum dynamics simulations found the Qx and Qy states to be energetically close and therefore strongly coupled. Here, we analyze the strong coupling between Qx and Qy via XAS, indicating promising possibilities for experimental observation. The excited-state energies, potential energy surfaces, and XAS are computed at the XMS-CASPT2 level of theory to capture the complex multireference character of chlorophyll excitations. In our simulated spectra, we could follow the ultrafast population transfer between Qx and Qy and thus draw conclusions about the strong vibrational coupling between them.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Attosecond spectroscopy, especially time-resolved X-ray absorption spectra (XAS), enables direct observation of ultrafast molecular dynamics. The complementary and even preceding development of theoretical simulations can offer the necessary guidance and stimulate new experiments. In this work, we simulated high-level XAS for the magnesium and nitrogen K-edge of chlorophyll a. In our previous work on the ultrafast relaxation process in the Q-band, our quantum dynamics simulations found the Qx and Qy states to be energetically close and therefore strongly coupled. Here, we analyze the strong coupling between Qx and Qy via XAS, indicating promising possibilities for experimental observation. The excited-state energies, potential energy surfaces, and XAS are computed at the XMS-CASPT2 level of theory to capture the complex multireference character of chlorophyll excitations. In our simulated spectra, we could follow the ultrafast population transfer between Qx and Qy and thus draw conclusions about the strong vibrational coupling between them.
1207.
T Lorenzen, B Diederichs, C Otieno Ogolla, B Butz, K Müller-Caspary
Aberration measurement by electron ptychography and consistency among different algorithms Journal Article
In: Applied Physics Letters, vol. 126, no. 8, pp. 081602, 2025, ISSN: 0003-6951.
@article{nokey,
title = {Aberration measurement by electron ptychography and consistency among different algorithms},
author = {T Lorenzen and B Diederichs and C Otieno Ogolla and B Butz and K M\"{u}ller-Caspary},
url = {https://doi.org/10.1063/5.0238580},
doi = {10.1063/5.0238580},
issn = {0003-6951},
year = {2025},
date = {2025-02-24},
journal = {Applied Physics Letters},
volume = {126},
number = {8},
pages = {081602},
abstract = {Control over and knowledge of the electron probe is important in all scanning transmission electron microscopy (STEM) techniques. This is emphasized especially in electron ptychography, where the accurate probe wave function is required to deconvolve illumination from the specimen. The majority of ptychographic algorithms, such as the extended ptychographic iterative engine, reconstruct the electron probe on a pixelated grid numerically self-consistently. Solutions are thus not necessarily bound to wave functions physically realizable by the optical system. A method is presented to characterize reconstructed probes by conventional lens aberrations. The fitted aberrations are then used to investigate the quality of the retrieved probes, and their consistency is examined in a systematic study using a 4D-STEM focal series recorded for a thin SnS2 2D flake. Additionally, the influences of partial coherence and limited electron dose on the retrieved probes are analyzed, and the usefulness of the retrieved probes for different ptychographic methods, such as single sideband, Wigner distribution deconvolution ptychography, and gradient descent-based schemes, is elucidated. Finally, applications for ptychography-driven alignments of aberration-correcting electron optics are outlined.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Control over and knowledge of the electron probe is important in all scanning transmission electron microscopy (STEM) techniques. This is emphasized especially in electron ptychography, where the accurate probe wave function is required to deconvolve illumination from the specimen. The majority of ptychographic algorithms, such as the extended ptychographic iterative engine, reconstruct the electron probe on a pixelated grid numerically self-consistently. Solutions are thus not necessarily bound to wave functions physically realizable by the optical system. A method is presented to characterize reconstructed probes by conventional lens aberrations. The fitted aberrations are then used to investigate the quality of the retrieved probes, and their consistency is examined in a systematic study using a 4D-STEM focal series recorded for a thin SnS2 2D flake. Additionally, the influences of partial coherence and limited electron dose on the retrieved probes are analyzed, and the usefulness of the retrieved probes for different ptychographic methods, such as single sideband, Wigner distribution deconvolution ptychography, and gradient descent-based schemes, is elucidated. Finally, applications for ptychography-driven alignments of aberration-correcting electron optics are outlined.
1206.
H Esmaielpour, P Schmiedeke, N Isaev, C Doganlar, M Döblinger, J J Finley, G Koblmüller
Hot carrier dynamics in III–V semiconductor nanowires under dominant radiative and Auger recombination Journal Article
In: Applied Physics Letters, vol. 126, no. 8, pp. 083505, 2025, ISSN: 0003-6951.
@article{nokey,
title = {Hot carrier dynamics in III\textendashV semiconductor nanowires under dominant radiative and Auger recombination},
author = {H Esmaielpour and P Schmiedeke and N Isaev and C Doganlar and M D\"{o}blinger and J J Finley and G Koblm\"{u}ller},
url = {https://doi.org/10.1063/5.0248247},
doi = {10.1063/5.0248247},
issn = {0003-6951},
year = {2025},
date = {2025-02-24},
journal = {Applied Physics Letters},
volume = {126},
number = {8},
pages = {083505},
abstract = {One-dimensional structures such as nanowires (NWs) show great promise in tailoring the rates of hot carrier thermalization in semiconductors with important implications for the design of efficient hot carrier absorbers. However, the fabrication of defect-free crystal structures and control of their intrinsic electronic properties can be challenging, raising concerns about the role of competing radiative and non-radiative recombination mechanisms that govern hot carrier effects. Here, we elucidate the impact of crystal purity and altered electronic properties on the hot carrier properties by comparing two classes of III\textendashV semiconductor NW arrays with similar bandgap energies and geometries, yet different crystal quality: one composed of GaAsSb NWs, which host antisite point defects but are free of planar stacking defects, and the other InGaAs NWs with a very high density of stacking defects. Photoluminescence spectroscopy demonstrates distinct hot carrier effects in both NW arrays; however, the InGaAs NWs exhibit stronger hot carrier effects, as evidenced by increased carrier temperature under identical photo-absorptivity. This difference arises from higher rates of Auger recombination in the InGaAs NWs due to their increased n-type conductivity, as confirmed by excitation power-dependent measurements. Our findings suggest that while enhancing material properties is crucial for improving the performance of hot carrier absorbers, optimizing conditions to increase the rates of Auger recombination will further boost the efficiency of these devices.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
One-dimensional structures such as nanowires (NWs) show great promise in tailoring the rates of hot carrier thermalization in semiconductors with important implications for the design of efficient hot carrier absorbers. However, the fabrication of defect-free crystal structures and control of their intrinsic electronic properties can be challenging, raising concerns about the role of competing radiative and non-radiative recombination mechanisms that govern hot carrier effects. Here, we elucidate the impact of crystal purity and altered electronic properties on the hot carrier properties by comparing two classes of III–V semiconductor NW arrays with similar bandgap energies and geometries, yet different crystal quality: one composed of GaAsSb NWs, which host antisite point defects but are free of planar stacking defects, and the other InGaAs NWs with a very high density of stacking defects. Photoluminescence spectroscopy demonstrates distinct hot carrier effects in both NW arrays; however, the InGaAs NWs exhibit stronger hot carrier effects, as evidenced by increased carrier temperature under identical photo-absorptivity. This difference arises from higher rates of Auger recombination in the InGaAs NWs due to their increased n-type conductivity, as confirmed by excitation power-dependent measurements. Our findings suggest that while enhancing material properties is crucial for improving the performance of hot carrier absorbers, optimizing conditions to increase the rates of Auger recombination will further boost the efficiency of these devices.
1205.
L Cusin, P Cieciórski, S Van Gele, F Heck, S Krause, P W Majewski, B V Lotsch, W Danowski, P Samorì
Synthesis of micrometre-thick oriented 2D covalent organic framework films by a kinetic polymerization pathway Journal Article
In: Nature Synthesis, 2025, ISSN: 2731-0582.
@article{nokey,
title = {Synthesis of micrometre-thick oriented 2D covalent organic framework films by a kinetic polymerization pathway},
author = {L Cusin and P Cieci\'{o}rski and S Van Gele and F Heck and S Krause and P W Majewski and B V Lotsch and W Danowski and P Samor\`{i}},
url = {https://doi.org/10.1038/s44160-025-00741-7},
doi = {10.1038/s44160-025-00741-7},
issn = {2731-0582},
year = {2025},
date = {2025-02-20},
journal = {Nature Synthesis},
abstract = {Despite advances in the field of 2D polymerization, the synthesis of high-quality, micrometre-thick films of oriented 2D covalent organic frameworks (COFs) remains challenging. Conventional approaches focusing on thermodynamic control of the polymerization pathway face a detrimental trade-off between orientation and thickness. Here we describe a straightforward method for preparing imine-linked 2D COF films with a near-perfect face-on orientation by leveraging kinetically trapped amorphous 3D covalent adaptable network (CAN) intermediates. These off-pathway intermediates are generated as coatings through solution casting, during which the CANs spontaneously align to relax tensile stresses induced by solvent evaporation. A subsequent lift-off process, followed by an amorphous-to-crystalline transformation under solvothermal conditions, converts the 3D-oriented polymer networks into thermodynamically stable, porous and free-standing 2D COF films. This versatile kinetic trapping strategy is suitable for a range of building blocks and network topologies, constituting a convenient synthetic tool for accessing high-quality, robust, large-area 2D COF films with a strongly aligned polycrystalline structure.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Despite advances in the field of 2D polymerization, the synthesis of high-quality, micrometre-thick films of oriented 2D covalent organic frameworks (COFs) remains challenging. Conventional approaches focusing on thermodynamic control of the polymerization pathway face a detrimental trade-off between orientation and thickness. Here we describe a straightforward method for preparing imine-linked 2D COF films with a near-perfect face-on orientation by leveraging kinetically trapped amorphous 3D covalent adaptable network (CAN) intermediates. These off-pathway intermediates are generated as coatings through solution casting, during which the CANs spontaneously align to relax tensile stresses induced by solvent evaporation. A subsequent lift-off process, followed by an amorphous-to-crystalline transformation under solvothermal conditions, converts the 3D-oriented polymer networks into thermodynamically stable, porous and free-standing 2D COF films. This versatile kinetic trapping strategy is suitable for a range of building blocks and network topologies, constituting a convenient synthetic tool for accessing high-quality, robust, large-area 2D COF films with a strongly aligned polycrystalline structure.
1204.
K-T Song, P M Schneider, I Grabovac, B Garlyyev, S A Watzele, A S Bandarenka
Influence of the Electrolyte pH on the Double Layer Capacitance of Polycrystalline Pt and Au Electrodes in Acidic Solutions Journal Article
In: ChemElectroChem, vol. 12, no. 4, pp. e202400587, 2025, ISSN: 2196-0216.
@article{nokey,
title = {Influence of the Electrolyte pH on the Double Layer Capacitance of Polycrystalline Pt and Au Electrodes in Acidic Solutions},
author = {K-T Song and P M Schneider and I Grabovac and B Garlyyev and S A Watzele and A S Bandarenka},
url = {https://doi.org/10.1002/celc.202400587},
doi = {https://doi.org/10.1002/celc.202400587},
issn = {2196-0216},
year = {2025},
date = {2025-02-16},
journal = {ChemElectroChem},
volume = {12},
number = {4},
pages = {e202400587},
abstract = {Abstract A deeper understanding of electrified solid/liquid interfaces of polycrystalline materials is crucial for optimizing energy conversion and storage devices, such as fuel cells, electrolyzers, and supercapacitors. After more than a century of research, the double-layer capacitance (CDL) has proven to be one of the few relatively easily experimentally accessible quantitative measures for characterizing such interfaces. However, despite their great importance, systematic CDL measurements are still not frequently associated with other interfacial properties. This work investigates the effect of the electrolyte pH on the CDL for polycrystalline platinum (Pt(pc)) and gold (Au(pc)) electrodes using cyclic voltammetry and impedance spectroscopy in acidic solutions with a pH ranging from 0 to 2 without adding any supporting electrolyte. Interestingly, under these conditions, the CDL for the Pt(pc) electrode increases with increasing electrolyte pH, while the CDL for the Au(pc) electrode shows the opposite trend. The increasing trend for Pt(pc) cannot be quantitatively described by the classical Stern model due to the stronger adsorption phenomenon on Pt surfaces. Moreover, positive linear trends with pH were found for the potentials of minimum CDL values and the potentials of maximum entropy for both electrodes, which closely correlate with reaction activities. However, the transition potentials of the constant phase element exponent (an element commonly used to approximate the behavior of the double layer in experiments) are only observed for the Pt electrode due to the phase transitions within the hydrogen adsorption/desorption and double-layer regions. These findings pose an important step toward revealing the interplay between essential interfacial parameters, which is crucial for a complete understanding of the electrical double layer.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract A deeper understanding of electrified solid/liquid interfaces of polycrystalline materials is crucial for optimizing energy conversion and storage devices, such as fuel cells, electrolyzers, and supercapacitors. After more than a century of research, the double-layer capacitance (CDL) has proven to be one of the few relatively easily experimentally accessible quantitative measures for characterizing such interfaces. However, despite their great importance, systematic CDL measurements are still not frequently associated with other interfacial properties. This work investigates the effect of the electrolyte pH on the CDL for polycrystalline platinum (Pt(pc)) and gold (Au(pc)) electrodes using cyclic voltammetry and impedance spectroscopy in acidic solutions with a pH ranging from 0 to 2 without adding any supporting electrolyte. Interestingly, under these conditions, the CDL for the Pt(pc) electrode increases with increasing electrolyte pH, while the CDL for the Au(pc) electrode shows the opposite trend. The increasing trend for Pt(pc) cannot be quantitatively described by the classical Stern model due to the stronger adsorption phenomenon on Pt surfaces. Moreover, positive linear trends with pH were found for the potentials of minimum CDL values and the potentials of maximum entropy for both electrodes, which closely correlate with reaction activities. However, the transition potentials of the constant phase element exponent (an element commonly used to approximate the behavior of the double layer in experiments) are only observed for the Pt electrode due to the phase transitions within the hydrogen adsorption/desorption and double-layer regions. These findings pose an important step toward revealing the interplay between essential interfacial parameters, which is crucial for a complete understanding of the electrical double layer.
1203.
A Semerci, J Urieta-Mora, S Driessen, A Buyruk, R Hooijer, A Molina-Ontoria, B Alkan, S Akin, M Fanetti, H Balakrishnan, A Hartschuh, S Tao, N Martín, P Müller-Buschbaum, S Emin, T Ameri
The Role of Fluorine-Functionalized Organic Spacers for Defect Passivation and Low-Dimensional Phase Formation in 3D MAPI Perovskite Solar Cells Journal Article
In: Advanced Functional Materials, vol. n/a, no. n/a, pp. 2423109, 2025, ISSN: 1616-301X.
@article{nokey,
title = {The Role of Fluorine-Functionalized Organic Spacers for Defect Passivation and Low-Dimensional Phase Formation in 3D MAPI Perovskite Solar Cells},
author = {A Semerci and J Urieta-Mora and S Driessen and A Buyruk and R Hooijer and A Molina-Ontoria and B Alkan and S Akin and M Fanetti and H Balakrishnan and A Hartschuh and S Tao and N Mart\'{i}n and P M\"{u}ller-Buschbaum and S Emin and T Ameri},
url = {https://doi.org/10.1002/adfm.202423109},
doi = {https://doi.org/10.1002/adfm.202423109},
issn = {1616-301X},
year = {2025},
date = {2025-02-14},
journal = {Advanced Functional Materials},
volume = {n/a},
number = {n/a},
pages = {2423109},
abstract = {Abstract Widespread application of organic-inorganic halide perovskites (OIHP) still faces a major obstacle in mitigating moisture-induced degradation. Integrating organic spacers, as defect passivation facilitators along with low-dimensional phase (LDP) formation is an effective approach to enhance the efficiency and robustness of 3D methyl ammonium lead iodide (MAPI) in photovoltaics (PV). Here, the formamidinium cation (FA+) employing 3,5-difluorobenzene-1-carboximidamidium iodide (2F), 4-(trifluoromethyl)benzene-1-carboximidamidium iodide (3F), and 2,3,4,5,6-pentafluorobenzene-1-carboximidamidium iodide (5F) organic spacers as passivation layer in 3D/LDP OIHP solar cells is utilized. Fluorine atom position and quantity in organic spacers change the optoelectronic characteristics of the perovskites, enhancing hydrophobicity, facilitating LDP formation, and augmenting dipole moments, thereby facilitating charge separation processes. PV performance analysis reveals that 3F-treated 3D/LDP devices achieve the highest efficiency of 19.22%. Experimental results and density functional theory (DFT) studies attribute the higher performance of 3F-modified devices to effective LDP formation, enhanced passivation of defect states at perovskite surfaces and grain boundaries, the highest dipole moment and lowest band gap among the evaluated spacers. The stability tests show that, after 1000 h, 3F- and 5F-modified 3D/LDP OIHP devices retain over 85% of their initial efficiency. This research opens novel avenues for designing appropriate organic spacers to attenuate defects in 3D/LDP PV devices.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract Widespread application of organic-inorganic halide perovskites (OIHP) still faces a major obstacle in mitigating moisture-induced degradation. Integrating organic spacers, as defect passivation facilitators along with low-dimensional phase (LDP) formation is an effective approach to enhance the efficiency and robustness of 3D methyl ammonium lead iodide (MAPI) in photovoltaics (PV). Here, the formamidinium cation (FA+) employing 3,5-difluorobenzene-1-carboximidamidium iodide (2F), 4-(trifluoromethyl)benzene-1-carboximidamidium iodide (3F), and 2,3,4,5,6-pentafluorobenzene-1-carboximidamidium iodide (5F) organic spacers as passivation layer in 3D/LDP OIHP solar cells is utilized. Fluorine atom position and quantity in organic spacers change the optoelectronic characteristics of the perovskites, enhancing hydrophobicity, facilitating LDP formation, and augmenting dipole moments, thereby facilitating charge separation processes. PV performance analysis reveals that 3F-treated 3D/LDP devices achieve the highest efficiency of 19.22%. Experimental results and density functional theory (DFT) studies attribute the higher performance of 3F-modified devices to effective LDP formation, enhanced passivation of defect states at perovskite surfaces and grain boundaries, the highest dipole moment and lowest band gap among the evaluated spacers. The stability tests show that, after 1000 h, 3F- and 5F-modified 3D/LDP OIHP devices retain over 85% of their initial efficiency. This research opens novel avenues for designing appropriate organic spacers to attenuate defects in 3D/LDP PV devices.
1202.
Z Li, S Vagin, J Zhang, R Guo, K Sun, X Jiang, T Guan, M Schwartzkopf, B Rieger, C-Q Ma, P Müller-Buschbaum
Suppressed Degradation Process of PBDB-TF-T1:BTP-4F-12-Based Organic Solar Cells with Solid Additive Atums Green Journal Article
In: ACS Applied Materials & Interfaces, vol. 17, no. 6, pp. 9475-9484, 2025, ISSN: 1944-8244.
@article{nokey,
title = {Suppressed Degradation Process of PBDB-TF-T1:BTP-4F-12-Based Organic Solar Cells with Solid Additive Atums Green},
author = {Z Li and S Vagin and J Zhang and R Guo and K Sun and X Jiang and T Guan and M Schwartzkopf and B Rieger and C-Q Ma and P M\"{u}ller-Buschbaum},
url = {https://doi.org/10.1021/acsami.4c21699},
doi = {10.1021/acsami.4c21699},
issn = {1944-8244},
year = {2025},
date = {2025-02-12},
journal = {ACS Applied Materials \& Interfaces},
volume = {17},
number = {6},
pages = {9475-9484},
abstract = {Solid additives have garnered significant attention due to their numerous advantages over liquid additives. This study explores the potential of the green-fluorescent conjugated polymer denoted Atums Green as a solid additive in green-solvent-based PBDB-TF-T1:BTP-4F-12 solar cells. Even tiny amounts of Atums Green doping significantly improve the device performance. For the reference solar cell without any additive, we find that device degradation is not caused by chemical redox reactions but by changes in crystallinity and microstructure evolution during aging in air under illumination. Operando GIWAXS and GISAXS are used to investigate the structure evolution. We discover a four-stage degradation process for the reference cell. In general, the lattice spacing and crystallite coherence length decrease, while the domain sizes increase, which causes the loss of shirt-circuit current JSC and fill factor FF. Furthermore, a decomposition component is detected in GIWAXS and GISAXS, corresponding to the loss of the open-circuit voltage VOC. Atums Green doping effectively suppresses the evolution of crystallinity and domain sizes as well as the continuous decomposition, thereby enhancing the device stability under illumination in air. This finding reveals the kinetic degradation process of organic solar cells, establishes a correlation between the morphological properties and device performance, and further demonstrates the promising potential of Atums Green doping in organic solar cells.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Solid additives have garnered significant attention due to their numerous advantages over liquid additives. This study explores the potential of the green-fluorescent conjugated polymer denoted Atums Green as a solid additive in green-solvent-based PBDB-TF-T1:BTP-4F-12 solar cells. Even tiny amounts of Atums Green doping significantly improve the device performance. For the reference solar cell without any additive, we find that device degradation is not caused by chemical redox reactions but by changes in crystallinity and microstructure evolution during aging in air under illumination. Operando GIWAXS and GISAXS are used to investigate the structure evolution. We discover a four-stage degradation process for the reference cell. In general, the lattice spacing and crystallite coherence length decrease, while the domain sizes increase, which causes the loss of shirt-circuit current JSC and fill factor FF. Furthermore, a decomposition component is detected in GIWAXS and GISAXS, corresponding to the loss of the open-circuit voltage VOC. Atums Green doping effectively suppresses the evolution of crystallinity and domain sizes as well as the continuous decomposition, thereby enhancing the device stability under illumination in air. This finding reveals the kinetic degradation process of organic solar cells, establishes a correlation between the morphological properties and device performance, and further demonstrates the promising potential of Atums Green doping in organic solar cells.
1201.
P Ufondu, Sakshi, T D Boyko, M M Pointner, W Schnick, A Moewes
Lone Pair and Unique N-Bridging of Novel Titanium Nitridophosphate Journal Article
In: Advanced Science, vol. 12, pp. 2412830, 2025, ISSN: 2198-3844.
@article{nokey,
title = {Lone Pair and Unique N-Bridging of Novel Titanium Nitridophosphate},
author = {P Ufondu and Sakshi and T D Boyko and M M Pointner and W Schnick and A Moewes},
url = {https://doi.org/10.1002/advs.202412830},
doi = {https://doi.org/10.1002/advs.202412830},
issn = {2198-3844},
year = {2025},
date = {2025-02-11},
urldate = {2025-02-11},
journal = {Advanced Science},
volume = {12},
pages = {2412830},
abstract = {Abstract In exploring advanced materials for solar power, the novel titanium nitridophosphate (TiP4N8) stands out due to its unique linear nitrogen bridging. To investigate the elemental interactions responsible for the photovoltaic performance under visible light, the titanium L2, 3-edges and nitrogen K-edge are specifically explored using X-ray absorption spectroscopy (XAS), X-ray emission spectroscopy (XES), and resonant inelastic X-ray scattering (RIXS) techniques to map the unoccupied and occupied electronic states. It is shown that the indirect interaction between the linear nitrogen bearing the lone pair and titanium is responsible for the bandgap of 1.55 ± 0.30 eV and 1.77 ± 0.30 eV in the ?- and α-TiP4N8 phases as well as the stability of the α-phase. The formal oxidation state of the Ti ion in the ?- and α-phases are also validated to be trivalent (Ti+3) and both trivalent (Ti+3) and tetravalent (Ti+4), respectively.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract In exploring advanced materials for solar power, the novel titanium nitridophosphate (TiP4N8) stands out due to its unique linear nitrogen bridging. To investigate the elemental interactions responsible for the photovoltaic performance under visible light, the titanium L2, 3-edges and nitrogen K-edge are specifically explored using X-ray absorption spectroscopy (XAS), X-ray emission spectroscopy (XES), and resonant inelastic X-ray scattering (RIXS) techniques to map the unoccupied and occupied electronic states. It is shown that the indirect interaction between the linear nitrogen bearing the lone pair and titanium is responsible for the bandgap of 1.55 ± 0.30 eV and 1.77 ± 0.30 eV in the ?- and α-TiP4N8 phases as well as the stability of the α-phase. The formal oxidation state of the Ti ion in the ?- and α-phases are also validated to be trivalent (Ti+3) and both trivalent (Ti+3) and tetravalent (Ti+4), respectively.
1200.
C Schott, L Hofbauer, E Gubanova, P Schneider, A S Bandarenka
Scanning impedance microscopy under oxygen reduction reaction conditions. Proof of the concept Journal Article
In: Electrochimica Acta, vol. 513, pp. 145533, 2025, ISSN: 0013-4686.
@article{nokey,
title = {Scanning impedance microscopy under oxygen reduction reaction conditions. Proof of the concept},
author = {C Schott and L Hofbauer and E Gubanova and P Schneider and A S Bandarenka},
url = {https://www.sciencedirect.com/science/article/pii/S0013468624017699},
doi = {https://doi.org/10.1016/j.electacta.2024.145533},
issn = {0013-4686},
year = {2025},
date = {2025-02-10},
journal = {Electrochimica Acta},
volume = {513},
pages = {145533},
abstract = {In this study, we demonstrate that localized electrochemical impedance spectroscopy (LEIS) can successfully probe the solid-liquid interface of a model gold surface in low-concentrated aqueous electrolytes. The approach utilizes scanning electrochemical microscopy (SECM) under potential control of the sample, marking a notable improvement over previous SECM-based LEIS studies, which were conducted under open circuit potential conditions. The accuracy of the results was validated by comparing the interfacial parameters, such as the double-layer capacitance minimum and the potential of zero charge, with the results obtained from conventional global measurements. Additionally, local kinetic parameters for the oxygen reduction reaction (ORR) were examined via LEIS by fitting the acquired impedance spectra to a simplified, physical equivalent circuit model. Gold was chosen as a model surface for the ORR with its well-defined ORR potential region due to the absence of hydrogen adsorption and overlapping OH⁻ adsorption. The local kinetic parameter determined from the LEIS experiments corresponds to the apparent rate coefficient (kapp) of the ORR, reflecting the average kapp of individual active sites within the probed area. The dependence of kapp on the ORR overpotential aligns well with the kinetics of the 2-electron reduction of O2 taking place at the gold sample. This proof-of-concept study demonstrates that SECM-based LEIS serves as a powerful tool for the advanced characterization of complex electrochemical interfaces for future experiments, especially those with heterogeneities or different structures/materials.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In this study, we demonstrate that localized electrochemical impedance spectroscopy (LEIS) can successfully probe the solid-liquid interface of a model gold surface in low-concentrated aqueous electrolytes. The approach utilizes scanning electrochemical microscopy (SECM) under potential control of the sample, marking a notable improvement over previous SECM-based LEIS studies, which were conducted under open circuit potential conditions. The accuracy of the results was validated by comparing the interfacial parameters, such as the double-layer capacitance minimum and the potential of zero charge, with the results obtained from conventional global measurements. Additionally, local kinetic parameters for the oxygen reduction reaction (ORR) were examined via LEIS by fitting the acquired impedance spectra to a simplified, physical equivalent circuit model. Gold was chosen as a model surface for the ORR with its well-defined ORR potential region due to the absence of hydrogen adsorption and overlapping OH⁻ adsorption. The local kinetic parameter determined from the LEIS experiments corresponds to the apparent rate coefficient (kapp) of the ORR, reflecting the average kapp of individual active sites within the probed area. The dependence of kapp on the ORR overpotential aligns well with the kinetics of the 2-electron reduction of O2 taking place at the gold sample. This proof-of-concept study demonstrates that SECM-based LEIS serves as a powerful tool for the advanced characterization of complex electrochemical interfaces for future experiments, especially those with heterogeneities or different structures/materials.
1199.
M J Feil, S Leisibach, M Becherer, K Krischer
Stability of the Au/electrolyte interface during hydrogen evolution: A Cyclic Plasmo-Voltammetry study Journal Article
In: Electrochimica Acta, vol. 513, pp. 145509, 2025, ISSN: 0013-4686.
@article{nokey,
title = {Stability of the Au/electrolyte interface during hydrogen evolution: A Cyclic Plasmo-Voltammetry study},
author = {M J Feil and S Leisibach and M Becherer and K Krischer},
url = {https://www.sciencedirect.com/science/article/pii/S0013468624017456},
doi = {https://doi.org/10.1016/j.electacta.2024.145509},
issn = {0013-4686},
year = {2025},
date = {2025-02-10},
journal = {Electrochimica Acta},
volume = {513},
pages = {145509},
abstract = {Metal-electrolyte interfaces are dynamic entities, the potential and electrolyte dependent mobility of the metal atoms leading to surface restructuring with possible dissolution and degradation. In this work, we investigate the stability of the Au/aqueous electrolyte interface with in situ differential Cyclic Plasmo-Voltammetry (dCPV), augmented by ex situ atomic force microscopy and finite differential time domain simulations. We demonstrate that even the onset of hydrogen evolution is accompanied by pronounced morphological changes of the interface which are by far more prominent than those occurring during Au oxidation and reduction. Furthermore, the stability of the interface heavily depends on pH, the degradation of the electrode being considerably stronger in acidic than in neutral electrolyte. In addition, a clear hydrogen adsorption peak was observed in neutral electrolytes during the cathodic scan, which was more pronounced on a freshly prepared Au electrode than on an aged one. The measured dCPVs in acidic and neutral electrolytes can be explained consistently assuming that (1) adsorbed hydrogen is absorbed into the subsurface region of the Au electrode once HER starts; its subsequent removal as molecular hydrogen causes morphological changes; (2) in the presence of metal cations, adsorbed hydrogen is stabilized through the formation of ternary metal hydrides on the gold surface that stabilize the surface Au-H bonds and hinder further absorption of H into the subsurface region as well as the release of hydrogen into the electrolyte.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Metal-electrolyte interfaces are dynamic entities, the potential and electrolyte dependent mobility of the metal atoms leading to surface restructuring with possible dissolution and degradation. In this work, we investigate the stability of the Au/aqueous electrolyte interface with in situ differential Cyclic Plasmo-Voltammetry (dCPV), augmented by ex situ atomic force microscopy and finite differential time domain simulations. We demonstrate that even the onset of hydrogen evolution is accompanied by pronounced morphological changes of the interface which are by far more prominent than those occurring during Au oxidation and reduction. Furthermore, the stability of the interface heavily depends on pH, the degradation of the electrode being considerably stronger in acidic than in neutral electrolyte. In addition, a clear hydrogen adsorption peak was observed in neutral electrolytes during the cathodic scan, which was more pronounced on a freshly prepared Au electrode than on an aged one. The measured dCPVs in acidic and neutral electrolytes can be explained consistently assuming that (1) adsorbed hydrogen is absorbed into the subsurface region of the Au electrode once HER starts; its subsequent removal as molecular hydrogen causes morphological changes; (2) in the presence of metal cations, adsorbed hydrogen is stabilized through the formation of ternary metal hydrides on the gold surface that stabilize the surface Au-H bonds and hinder further absorption of H into the subsurface region as well as the release of hydrogen into the electrolyte.
1198.
C C Aletsee, P Neumann, I Chorkendorff, M Tschurl, U Heiz
Tertiary Alcohols as Mechanistic Probes for Photocatalysis: the Gas-Phase Reaction of 2-Methyl-2-Pentanol on Titania P25 in a Microphotoreactor Journal Article
In: ACS Catalysis, vol. 15, no. 3, pp. 2584-2594, 2025.
@article{nokey,
title = {Tertiary Alcohols as Mechanistic Probes for Photocatalysis: the Gas-Phase Reaction of 2-Methyl-2-Pentanol on Titania P25 in a Microphotoreactor},
author = {C C Aletsee and P Neumann and I Chorkendorff and M Tschurl and U Heiz},
url = {https://doi.org/10.1021/acscatal.4c07001},
doi = {10.1021/acscatal.4c07001},
year = {2025},
date = {2025-02-07},
journal = {ACS Catalysis},
volume = {15},
number = {3},
pages = {2584-2594},
abstract = {Despite intense research in heterogeneous photocatalysis, a lack of mechanistic understanding still hinders the rational design of efficient photocatalysts to make them competitive with thermal processes that currently dominate the industry. This study elucidates the underlying mechanism of photoreactions by employing tertiary alcohols as probe molecules on a titania P25 catalyst for the understanding of photocatalytic reactions on a molecular scale. We show that the reactions do not follow the commonly assumed reaction mechanism of separate but coupled redox reactions. Instead, the gas-phase reaction occurs selectively via a homolytic bond cleavage of the long alkyl chain, leading to the formation of the corresponding ketone and an alkane, as exemplified for 2-methyl-2-pentanol at ambient pressure. The alkane stems predominantly from the recombination of the alkyl-moiety with surface hydrogen. Additionally, we demonstrate that the alkyl moiety can also undergo a dimerization reaction forming a long chain alkane, which is facilitated on bare TiO2. The high time-resolution enabled by the used microreactor allowed us to confirm that this side reaction is a higher-order process, which is governed by the alcohol surface coverage on TiO2. The parallels of the observed reaction properties with studies performed on a TiO2(110) single crystal in vacuum reveal that no significant pressure and material gap exists. On the one hand, this strongly suggests that also the reaction mechanism for the conversion of other alcohols must be reconsidered on titania-based photocatalysts and, on the other hand, demonstrates the potential of tertiary alcohols as mechanistic probes in photocatalysis. Moreover, the highly selective reactions of tertiary alcohols may open up alternative routes for chemical synthesis.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Despite intense research in heterogeneous photocatalysis, a lack of mechanistic understanding still hinders the rational design of efficient photocatalysts to make them competitive with thermal processes that currently dominate the industry. This study elucidates the underlying mechanism of photoreactions by employing tertiary alcohols as probe molecules on a titania P25 catalyst for the understanding of photocatalytic reactions on a molecular scale. We show that the reactions do not follow the commonly assumed reaction mechanism of separate but coupled redox reactions. Instead, the gas-phase reaction occurs selectively via a homolytic bond cleavage of the long alkyl chain, leading to the formation of the corresponding ketone and an alkane, as exemplified for 2-methyl-2-pentanol at ambient pressure. The alkane stems predominantly from the recombination of the alkyl-moiety with surface hydrogen. Additionally, we demonstrate that the alkyl moiety can also undergo a dimerization reaction forming a long chain alkane, which is facilitated on bare TiO2. The high time-resolution enabled by the used microreactor allowed us to confirm that this side reaction is a higher-order process, which is governed by the alcohol surface coverage on TiO2. The parallels of the observed reaction properties with studies performed on a TiO2(110) single crystal in vacuum reveal that no significant pressure and material gap exists. On the one hand, this strongly suggests that also the reaction mechanism for the conversion of other alcohols must be reconsidered on titania-based photocatalysts and, on the other hand, demonstrates the potential of tertiary alcohols as mechanistic probes in photocatalysis. Moreover, the highly selective reactions of tertiary alcohols may open up alternative routes for chemical synthesis.
1197.
E Sirotti, B Scaparra, S Böhm, F Pantle, L I Wagner, F Rauh, F Munnik, C-M Jiang, M Kuhl, K Müller, J Eichhorn, V Streibel, I D Sharp
Oxygen Incorporation as a Route to Nondegenerate Zinc Nitride Semiconductor Thin Films Journal Article
In: ACS Applied Materials & Interfaces, vol. 17, no. 5, pp. 7958-7968, 2025, ISSN: 1944-8244.
@article{nokey,
title = {Oxygen Incorporation as a Route to Nondegenerate Zinc Nitride Semiconductor Thin Films},
author = {E Sirotti and B Scaparra and S B\"{o}hm and F Pantle and L I Wagner and F Rauh and F Munnik and C-M Jiang and M Kuhl and K M\"{u}ller and J Eichhorn and V Streibel and I D Sharp},
url = {https://doi.org/10.1021/acsami.4c16921},
doi = {10.1021/acsami.4c16921},
issn = {1944-8244},
year = {2025},
date = {2025-02-05},
journal = {ACS Applied Materials \& Interfaces},
volume = {17},
number = {5},
pages = {7958-7968},
abstract = {Zinc nitride (Zn3N2) comprises earth-abundant elements, possesses a small direct bandgap, and is characterized by high electron mobility. While these characteristics make the material a promising compound semiconductor for various optoelectronic applications, including photovoltaics and thin-film transistors, it commonly exhibits unintentional degenerate n-type conductivity. This degenerate character has significantly impeded the development of Zn3N2 for technological applications and is commonly assumed to arise from incorporation of oxygen impurities. However, consistent understanding and control of the role of native and impurity defects on the optoelectronic properties of this otherwise promising semiconductor have not yet emerged. Here, we systematically synthesize epitaxial Zn3N2 thin films with controlled oxygen impurity concentrations of up to 20 at % by plasma-assisted molecular beam epitaxy (PA-MBE). Contrary to expectations, we find that oxygen does not lead to degenerate conductivity but instead serves as a compensating defect, the control of which can be used to achieve nondegenerate semiconducting thin films with free electron concentrations in the range of 1017 cm\textendash3, while retaining high mobilities in excess of 200 cm2 V\textendash1 s\textendash1. This understanding of the beneficial role of oxygen thus provides a route to controllably synthesize nondegenerate O-doped Zn3N2 for optoelectronic applications.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Zinc nitride (Zn3N2) comprises earth-abundant elements, possesses a small direct bandgap, and is characterized by high electron mobility. While these characteristics make the material a promising compound semiconductor for various optoelectronic applications, including photovoltaics and thin-film transistors, it commonly exhibits unintentional degenerate n-type conductivity. This degenerate character has significantly impeded the development of Zn3N2 for technological applications and is commonly assumed to arise from incorporation of oxygen impurities. However, consistent understanding and control of the role of native and impurity defects on the optoelectronic properties of this otherwise promising semiconductor have not yet emerged. Here, we systematically synthesize epitaxial Zn3N2 thin films with controlled oxygen impurity concentrations of up to 20 at % by plasma-assisted molecular beam epitaxy (PA-MBE). Contrary to expectations, we find that oxygen does not lead to degenerate conductivity but instead serves as a compensating defect, the control of which can be used to achieve nondegenerate semiconducting thin films with free electron concentrations in the range of 1017 cm–3, while retaining high mobilities in excess of 200 cm2 V–1 s–1. This understanding of the beneficial role of oxygen thus provides a route to controllably synthesize nondegenerate O-doped Zn3N2 for optoelectronic applications.
1196.
J Reich, S Kaiser, A Bourgund, M Krinninger, U Heiz, F Esch, B A J Lechner
Exploring the atomic-scale dynamics of Fe3O4(001) at catalytically relevant temperatures using FastSTM Journal Article
In: Surface Science, vol. 752, pp. 122634, 2025, ISSN: 0039-6028.
@article{nokey,
title = {Exploring the atomic-scale dynamics of Fe3O4(001) at catalytically relevant temperatures using FastSTM},
author = {J Reich and S Kaiser and A Bourgund and M Krinninger and U Heiz and F Esch and B A J Lechner},
url = {https://www.sciencedirect.com/science/article/pii/S0039602824001857},
doi = {https://doi.org/10.1016/j.susc.2024.122634},
issn = {0039-6028},
year = {2025},
date = {2025-02-01},
urldate = {2025-02-01},
journal = {Surface Science},
volume = {752},
pages = {122634},
abstract = {Surfaces and interfaces of functional nanoscale materials are typically highly dynamic when employed at elevated temperatures. Both, lateral surface and vertical bulk exchange diffusion processes set in, which can be relevant for applications such as heterogeneous catalysis. Time-resolved scanning tunneling microscopy (STM) is being pushed to ever faster measurement modes to follow such dynamic phenomena in situ. Here, we present FastSTM movies monitoring a range of atomic-scale dynamics of a prototypical reducible oxide catalyst support, Fe3O4(001), at elevated temperatures. Antiphase domain boundaries between two domains of the reconstructed surface exhibit local mobility from around 350 K, while Fe-rich point defects, in a stable equilibrium with the bulk, appear to diffuse in a peculiar zigzag pattern above 500 K. Finally, exploiting the diffusivity of Fe interstitials, we follow the propagation of step edges in the topmost atomic layer of the Fe3O4(001) surface in an oxygen atmosphere.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Surfaces and interfaces of functional nanoscale materials are typically highly dynamic when employed at elevated temperatures. Both, lateral surface and vertical bulk exchange diffusion processes set in, which can be relevant for applications such as heterogeneous catalysis. Time-resolved scanning tunneling microscopy (STM) is being pushed to ever faster measurement modes to follow such dynamic phenomena in situ. Here, we present FastSTM movies monitoring a range of atomic-scale dynamics of a prototypical reducible oxide catalyst support, Fe3O4(001), at elevated temperatures. Antiphase domain boundaries between two domains of the reconstructed surface exhibit local mobility from around 350 K, while Fe-rich point defects, in a stable equilibrium with the bulk, appear to diffuse in a peculiar zigzag pattern above 500 K. Finally, exploiting the diffusivity of Fe interstitials, we follow the propagation of step edges in the topmost atomic layer of the Fe3O4(001) surface in an oxygen atmosphere.
1195.
J Pittrich, K Liang, L Dörringer, R Kienberger, U Heiz, A Kartouzian, H Iglev
From molecules to materials: SHG-CD microscopy of structured chiral films Journal Article
In: Applied Surface Science, vol. 680, pp. 161331, 2025, ISSN: 0169-4332.
@article{nokey,
title = {From molecules to materials: SHG-CD microscopy of structured chiral films},
author = {J Pittrich and K Liang and L D\"{o}rringer and R Kienberger and U Heiz and A Kartouzian and H Iglev},
url = {https://www.sciencedirect.com/science/article/pii/S0169433224020464},
doi = {https://doi.org/10.1016/j.apsusc.2024.161331},
issn = {0169-4332},
year = {2025},
date = {2025-01-30},
journal = {Applied Surface Science},
volume = {680},
pages = {161331},
abstract = {The interplay between molecular and structural chirality as a function of local sample morphology determines the nonlinear optical properties of many organic and hybrid organic\textendashinorganic thin films. Here, we used second harmonic generation circular dichroism (SHG-CD) microscopy of thin molecular films of 1,1′-bi-2-naphthol (R-BINOL) as a research model. Our results show that the SHG signal measured at frequencies close to the electronic transition of BINOL molecules is resonantly enhanced by more than an order of magnitude compared to the non-resonant case. The extracted resonant SHG-CD signal is dominated by the chiral response of the molecule. In contrast, structural chirality determines the non-resonant SHG-CD images. We see clear evidence that the interference of the SHG signals caused by the molecular and structural chirality can lead to a decrease in the overall SHG intensity when both SHG signals are out of phase. These findings highlight the intricate relationship between molecular and structural chirality on the one hand and structural morphology on the other hand and pave the way for novel applications by exploiting the chiroptic properties of thin films.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The interplay between molecular and structural chirality as a function of local sample morphology determines the nonlinear optical properties of many organic and hybrid organic–inorganic thin films. Here, we used second harmonic generation circular dichroism (SHG-CD) microscopy of thin molecular films of 1,1′-bi-2-naphthol (R-BINOL) as a research model. Our results show that the SHG signal measured at frequencies close to the electronic transition of BINOL molecules is resonantly enhanced by more than an order of magnitude compared to the non-resonant case. The extracted resonant SHG-CD signal is dominated by the chiral response of the molecule. In contrast, structural chirality determines the non-resonant SHG-CD images. We see clear evidence that the interference of the SHG signals caused by the molecular and structural chirality can lead to a decrease in the overall SHG intensity when both SHG signals are out of phase. These findings highlight the intricate relationship between molecular and structural chirality on the one hand and structural morphology on the other hand and pave the way for novel applications by exploiting the chiroptic properties of thin films.
1194.
J Hao, P Liu, Z Zhou, H Liu, W Chen, P Müller-Buschbaum, J Cheng, K Wang, X W Sun, J-P Delville, M-H Delville
In: Nanoscale Advances, vol. 7, no. 6, pp. 1650-1662, 2025.
@article{nokey,
title = {Shape-tailored semiconductor dot-in-rods: optimizing CdS-shell growth for enhanced chiroptical properties via the rationalization of the role of temperature and time},
author = {J Hao and P Liu and Z Zhou and H Liu and W Chen and P M\"{u}ller-Buschbaum and J Cheng and K Wang and X W Sun and J-P Delville and M-H Delville},
url = {http://dx.doi.org/10.1039/D4NA01003E},
doi = {10.1039/D4NA01003E},
year = {2025},
date = {2025-01-29},
journal = {Nanoscale Advances},
volume = {7},
number = {6},
pages = {1650-1662},
abstract = {Colloidal chemistry provides an assortment of synthetic tools for tuning the shape of semiconductor nanocrystals. To fully exploit the shape- and structure-dependent properties of semiconductor nanorods, high-precision control on growth and design is essential. However, achieving this precision is highly challenging due to the high temperatures (\>350 °C) and short reaction times (\<8 minutes) often required for these reactions. In this study, we performed the first investigation on the impact of temperature and time on the CdS-shell growth of CdSe/CdS quantum rods. Our findings demonstrate that temperature plays a pivotal role in achieving ultra-thin shell dot-in-rods, which are crucial for enhancing chiroptical properties. The two-step process proposed here explains the shell growth of CdSe/CdS dot-in-rods (DRs). It involves finely-tuned isotropic shell growth in the first stage, followed by anisotropic length growth along the [0001] rod axis in the second step. This approach has two advantages: a systematic control of the shell thickness for different aspect ratios (ARs) and batch monodispersity. These DRs, with an ultra-thin CdS shell and a high AR, after modification with l/d cysteine molecules, exhibit significant enhancement of their ligand-induced chirality, with circular dichroism (CD) g-factor values as high as 10−3.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Colloidal chemistry provides an assortment of synthetic tools for tuning the shape of semiconductor nanocrystals. To fully exploit the shape- and structure-dependent properties of semiconductor nanorods, high-precision control on growth and design is essential. However, achieving this precision is highly challenging due to the high temperatures (>350 °C) and short reaction times (<8 minutes) often required for these reactions. In this study, we performed the first investigation on the impact of temperature and time on the CdS-shell growth of CdSe/CdS quantum rods. Our findings demonstrate that temperature plays a pivotal role in achieving ultra-thin shell dot-in-rods, which are crucial for enhancing chiroptical properties. The two-step process proposed here explains the shell growth of CdSe/CdS dot-in-rods (DRs). It involves finely-tuned isotropic shell growth in the first stage, followed by anisotropic length growth along the [0001] rod axis in the second step. This approach has two advantages: a systematic control of the shell thickness for different aspect ratios (ARs) and batch monodispersity. These DRs, with an ultra-thin CdS shell and a high AR, after modification with l/d cysteine molecules, exhibit significant enhancement of their ligand-induced chirality, with circular dichroism (CD) g-factor values as high as 10−3.
1193.
L F Huber, K Sun, M A Reus, C L Weindl, J E Heger, S V Roth, P Müller-Buschbaum
In: Advanced Materials Interfaces, vol. n/a, no. n/a, pp. 2400929, 2025, ISSN: 2196-7350.
@article{nokey,
title = {Beta-Lactoglobulin for Water-Based and Tunable Nanostructure Templating of Printed Titania Thin Films: The Influence of pH Value and Protein Concentration},
author = {L F Huber and K Sun and M A Reus and C L Weindl and J E Heger and S V Roth and P M\"{u}ller-Buschbaum},
url = {https://doi.org/10.1002/admi.202400929},
doi = {https://doi.org/10.1002/admi.202400929},
issn = {2196-7350},
year = {2025},
date = {2025-01-26},
journal = {Advanced Materials Interfaces},
volume = {n/a},
number = {n/a},
pages = {2400929},
abstract = {Abstract An environmentally friendly as well as scalable synthesis route of nanostructured titania thin films is of interest for many state-of-the-art devices, from solar cells to battery materials. Beta-lactoglobulin (\ss-lg) enables water-based and tunable titania thin film templating, allowing for different domain sizes, porosities, and morphologies. When printed with a slot-die coater, the titania films can be tailored to specific applications with simple changes to the solution chemistry. Films printed at acidic pH conditions form significantly different final morphologies than films printed at a neutral pH value. The protein concentration plays a more limited role in the final nanostructure. With in situ grazing incidence small-angle/wide-angle X-ray scattering (GISAXS/GIWAXS), the structure formation is followed with an excellent time resolution during the printing process. From the GISAXS measurements, the size evolution of the titania clusters is understood, showing significant differences for different pH values. Crystal phases and corresponding crystal orientations are investigated with GIWAXS. The combination of a water-based titania synthesis with the scalable film deposition via slot die coating makes the presented results interesting for potential environmentally friendly mass production of nanostructured titania films.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract An environmentally friendly as well as scalable synthesis route of nanostructured titania thin films is of interest for many state-of-the-art devices, from solar cells to battery materials. Beta-lactoglobulin (ß-lg) enables water-based and tunable titania thin film templating, allowing for different domain sizes, porosities, and morphologies. When printed with a slot-die coater, the titania films can be tailored to specific applications with simple changes to the solution chemistry. Films printed at acidic pH conditions form significantly different final morphologies than films printed at a neutral pH value. The protein concentration plays a more limited role in the final nanostructure. With in situ grazing incidence small-angle/wide-angle X-ray scattering (GISAXS/GIWAXS), the structure formation is followed with an excellent time resolution during the printing process. From the GISAXS measurements, the size evolution of the titania clusters is understood, showing significant differences for different pH values. Crystal phases and corresponding crystal orientations are investigated with GIWAXS. The combination of a water-based titania synthesis with the scalable film deposition via slot die coating makes the presented results interesting for potential environmentally friendly mass production of nanostructured titania films.
1192.
M Zipkat, A Koldemir, T Block, C Ceniza, T D Boyko, S Kläger, R M Pritzl, A Moewes, R Pöttgen, S S Rudel, W Schnick
Scalable Bulk Synthesis of Phase-Pure γ-Sn3N4 as a Model for an Argon-Flow-Mediated Metathesis Reaction Journal Article
In: Chemistry – A European Journal, vol. 31, pp. e202403745, 2025, ISSN: 0947-6539.
@article{nokey,
title = {Scalable Bulk Synthesis of Phase-Pure γ-Sn3N4 as a Model for an Argon-Flow-Mediated Metathesis Reaction},
author = {M Zipkat and A Koldemir and T Block and C Ceniza and T D Boyko and S Kl\"{a}ger and R M Pritzl and A Moewes and R P\"{o}ttgen and S S Rudel and W Schnick},
url = {https://doi.org/10.1002/chem.202403745},
doi = {https://doi.org/10.1002/chem.202403745},
issn = {0947-6539},
year = {2025},
date = {2025-01-23},
urldate = {2024-11-18},
journal = {Chemistry \textendash A European Journal},
volume = {31},
pages = {e202403745},
abstract = {Abstract Nitrides represent a promising class of materials for a variety of applications. However, bulk synthesis remains a challenging task due to the stability of the N2 molecule. In this study, we introduce a simple and scalable approach for synthesizing nitride bulk materials. Moderate reaction temperatures are achieved by using reactive starting materials, slow and continuous mixing of the starting materials, and by dissipating heat generated during the reaction. The impact on the synthesis of using different starting materials as nitrogen source and the influence of a flux were examined. ?-Sn3N4 was selected as the model compound. The synthesis of pure ?-Sn3N4 bulk material on a large scale has still been a challenge, although a few synthesis methods were already described in the literature. Here we synthesized ?-Sn3N4 by metathesis reaction of argon-diluted SnCl4 with Li3N, Mg3N2 or Ca3N2 as nitrogen sources. Products were characterized by powder X-ray diffraction, scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy, dynamic flash combustion analysis, hot gas extraction analysis, X-ray photoelectron spectroscopy, M\"{o}ssbauer spectroscopy and X-ray absorption and emission spectroscopy. Additionally, single-crystal diffraction data of ?-Sn?N?, previously unavailable, were successfully collected.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract Nitrides represent a promising class of materials for a variety of applications. However, bulk synthesis remains a challenging task due to the stability of the N2 molecule. In this study, we introduce a simple and scalable approach for synthesizing nitride bulk materials. Moderate reaction temperatures are achieved by using reactive starting materials, slow and continuous mixing of the starting materials, and by dissipating heat generated during the reaction. The impact on the synthesis of using different starting materials as nitrogen source and the influence of a flux were examined. ?-Sn3N4 was selected as the model compound. The synthesis of pure ?-Sn3N4 bulk material on a large scale has still been a challenge, although a few synthesis methods were already described in the literature. Here we synthesized ?-Sn3N4 by metathesis reaction of argon-diluted SnCl4 with Li3N, Mg3N2 or Ca3N2 as nitrogen sources. Products were characterized by powder X-ray diffraction, scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy, dynamic flash combustion analysis, hot gas extraction analysis, X-ray photoelectron spectroscopy, Mössbauer spectroscopy and X-ray absorption and emission spectroscopy. Additionally, single-crystal diffraction data of ?-Sn?N?, previously unavailable, were successfully collected.
1191.
R Shafei, P J Strobel, P J Schmidt, D Maganas, W Schnick, F Neese
A Combined Experimental and Computational Study on the Broadening Mechanism of the Luminescence in Narrow-Band Eu2+-Doped Phosphors Journal Article
In: The Journal of Physical Chemistry C, vol. 129, no. 2, pp. 1495-1505, 2025, ISSN: 1932-7447.
@article{nokey,
title = {A Combined Experimental and Computational Study on the Broadening Mechanism of the Luminescence in Narrow-Band Eu2+-Doped Phosphors},
author = {R Shafei and P J Strobel and P J Schmidt and D Maganas and W Schnick and F Neese},
url = {https://doi.org/10.1021/acs.jpcc.4c06912},
doi = {10.1021/acs.jpcc.4c06912},
issn = {1932-7447},
year = {2025},
date = {2025-01-16},
journal = {The Journal of Physical Chemistry C},
volume = {129},
number = {2},
pages = {1495-1505},
abstract = {In this work, we present a comprehensive study of the luminescence relaxation mechanism and the associated spectral broadening in a series of Eu2+-doped narrow-band phosphors. It is highlighted that the commonly used full-width at half-maximum (fwhm) is no longer a sensitive measure for quantifying the emission bandwidth of these materials. A thorough understanding of the factors contributing to the narrow bandwidth requires an explicit treatment of the magnetic structure of the ground and emissive excited state manifolds. This requires incorporating spin\textendashorbit coupling effects using wave function-based methods such as the complete active space self-consistent field combined with second-order N-electron valence state perturbation theory (CASSCF/NEVPT2). In addition, for the associated excited state dynamics calculations, one needs to consider vibronic coupling interactions on the basis of Franck\textendashCondon (FC), Herzberg\textendashTeller (HT), and, when necessary, pseudo Jahn\textendashTeller (PJT) coupling effects. Our analysis underscores that understanding and controlling the synergistic roles of these “static” and “dynamic” effects are essential for accurately assessing the narrow band emission relaxation in these systems. We show that these results can, in principle, be generalized to an arbitrary set of narrow-band phosphor candidates and can potentially aid the experimental efforts toward developing novel phosphors with enhanced luminescent properties.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In this work, we present a comprehensive study of the luminescence relaxation mechanism and the associated spectral broadening in a series of Eu2+-doped narrow-band phosphors. It is highlighted that the commonly used full-width at half-maximum (fwhm) is no longer a sensitive measure for quantifying the emission bandwidth of these materials. A thorough understanding of the factors contributing to the narrow bandwidth requires an explicit treatment of the magnetic structure of the ground and emissive excited state manifolds. This requires incorporating spin–orbit coupling effects using wave function-based methods such as the complete active space self-consistent field combined with second-order N-electron valence state perturbation theory (CASSCF/NEVPT2). In addition, for the associated excited state dynamics calculations, one needs to consider vibronic coupling interactions on the basis of Franck–Condon (FC), Herzberg–Teller (HT), and, when necessary, pseudo Jahn–Teller (PJT) coupling effects. Our analysis underscores that understanding and controlling the synergistic roles of these “static” and “dynamic” effects are essential for accurately assessing the narrow band emission relaxation in these systems. We show that these results can, in principle, be generalized to an arbitrary set of narrow-band phosphor candidates and can potentially aid the experimental efforts toward developing novel phosphors with enhanced luminescent properties.
1190.
K Endo, S Canossa, F Heck, D M Proserpio, M S Istek, F Stemmler, J Van Slageren, S Hartmann, A Hartschuh, B V Lotsch
Crystalline porous frameworks based on double extension of metal–organic and covalent organic linkages Journal Article
In: Nature Synthesis, 2025, ISSN: 2731-0582.
@article{nokey,
title = {Crystalline porous frameworks based on double extension of metal\textendashorganic and covalent organic linkages},
author = {K Endo and S Canossa and F Heck and D M Proserpio and M S Istek and F Stemmler and J Van Slageren and S Hartmann and A Hartschuh and B V Lotsch},
url = {https://doi.org/10.1038/s44160-024-00719-x},
doi = {10.1038/s44160-024-00719-x},
issn = {2731-0582},
year = {2025},
date = {2025-01-14},
journal = {Nature Synthesis},
abstract = {Reticular chemistry is a powerful strategy to design materials with fine-tuned chemical functionality and porosity, such as metal\textendashorganic frameworks (MOFs) and covalent organic frameworks (COFs). MOFs typically show high crystallinity due to their reversible coordinative bonds, and the organic backbone of COFs provides chemical stability. Here we synthesize metal\textendashorganic\textendashcovalent\textendashorganic frameworks (MOCOFs) that combine both crystallinity and stability in a single framework by the double extension of metal\textendashorganic and covalent organic linkages. Several MOCOFs are obtained by reaction between a cobalt aminoporphyrin and dialdehydes, which are interconnected by cobalt\textendashamine coordination and imine condensation to form three-dimensional networks. The MOCOFs exhibit chiral topological nets, large surface areas, high crystallinities and high chemical stabilities due to the two types of extended linkages. Thus, MOCOFs present a reticular design strategy that further diversifies the chemical and structural space of porous solids.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Reticular chemistry is a powerful strategy to design materials with fine-tuned chemical functionality and porosity, such as metal–organic frameworks (MOFs) and covalent organic frameworks (COFs). MOFs typically show high crystallinity due to their reversible coordinative bonds, and the organic backbone of COFs provides chemical stability. Here we synthesize metal–organic–covalent–organic frameworks (MOCOFs) that combine both crystallinity and stability in a single framework by the double extension of metal–organic and covalent organic linkages. Several MOCOFs are obtained by reaction between a cobalt aminoporphyrin and dialdehydes, which are interconnected by cobalt–amine coordination and imine condensation to form three-dimensional networks. The MOCOFs exhibit chiral topological nets, large surface areas, high crystallinities and high chemical stabilities due to the two types of extended linkages. Thus, MOCOFs present a reticular design strategy that further diversifies the chemical and structural space of porous solids.
1189.
D Meier, P Knecht, P Vezzoni Vicente, F Eratam, H Xu, T-L Lee, A Generalov, A Riss, B Yang, F Allegretti, P Feulner, J Reichert, J V Barth, A P Seitsonen, D A Duncan, A C Papageorgiou
Octaethyl vs Tetrabenzo Functionalized Ru Porphyrins on Ag(111): Molecular Conformation, Self-Assembly and Electronic Structure Journal Article
In: The Journal of Physical Chemistry C, vol. 129, no. 1, pp. 858-869, 2025, ISSN: 1932-7447.
@article{nokey,
title = {Octaethyl vs Tetrabenzo Functionalized Ru Porphyrins on Ag(111): Molecular Conformation, Self-Assembly and Electronic Structure},
author = {D Meier and P Knecht and P Vezzoni Vicente and F Eratam and H Xu and T-L Lee and A Generalov and A Riss and B Yang and F Allegretti and P Feulner and J Reichert and J V Barth and A P Seitsonen and D A Duncan and A C Papageorgiou},
url = {https://doi.org/10.1021/acs.jpcc.4c06978},
doi = {10.1021/acs.jpcc.4c06978},
issn = {1932-7447},
year = {2025},
date = {2025-01-09},
journal = {The Journal of Physical Chemistry C},
volume = {129},
number = {1},
pages = {858-869},
abstract = {Metalloporphyrins on interfaces offer a rich playground for functional materials and hence have been subjected to intense scrutiny over the past decades. As the same porphyrin macrocycle on the same surface may exhibit vastly different physicochemical properties depending on the metal center and its substituents, it is vital to have a thorough structural and chemical characterization of such systems. Here, we explore the distinctions arising from coverage and macrocycle substituents on the closely related ruthenium octaethyl porphyrin and ruthenium tetrabenzo porphyrin on Ag(111). Our investigation employs a multitechnique approach in ultrahigh vacuum, combining scanning tunneling microscopy, low-energy electron diffraction, photoelectron spectroscopy, normal incidence X-ray standing wave, and near-edge X-ray absorption fine structure, supported by density functional theory. This methodology allows for a thorough examination of the nuanced differences in the self-assembly, substrate modification, molecular conformation and adsorption height.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Metalloporphyrins on interfaces offer a rich playground for functional materials and hence have been subjected to intense scrutiny over the past decades. As the same porphyrin macrocycle on the same surface may exhibit vastly different physicochemical properties depending on the metal center and its substituents, it is vital to have a thorough structural and chemical characterization of such systems. Here, we explore the distinctions arising from coverage and macrocycle substituents on the closely related ruthenium octaethyl porphyrin and ruthenium tetrabenzo porphyrin on Ag(111). Our investigation employs a multitechnique approach in ultrahigh vacuum, combining scanning tunneling microscopy, low-energy electron diffraction, photoelectron spectroscopy, normal incidence X-ray standing wave, and near-edge X-ray absorption fine structure, supported by density functional theory. This methodology allows for a thorough examination of the nuanced differences in the self-assembly, substrate modification, molecular conformation and adsorption height.
1188.
J Lee, J Kim, G Posnjak, A Ershova, D Hayakawa, W M Shih, W B Rogers, Y Ke, T Liedl, S Lee
DNA Origami Colloidal Crystals: Opportunities and Challenges Journal Article
In: Nano Letters, vol. 25, no. 1, pp. 16-27, 2025, ISSN: 1530-6984.
@article{nokey,
title = {DNA Origami Colloidal Crystals: Opportunities and Challenges},
author = {J Lee and J Kim and G Posnjak and A Ershova and D Hayakawa and W M Shih and W B Rogers and Y Ke and T Liedl and S Lee},
url = {https://doi.org/10.1021/acs.nanolett.4c05041},
doi = {10.1021/acs.nanolett.4c05041},
issn = {1530-6984},
year = {2025},
date = {2025-01-08},
journal = {Nano Letters},
volume = {25},
number = {1},
pages = {16-27},
abstract = {Over the last three decades, colloidal crystallization has provided an easy-to-craft platform for mesoscale engineering of photonic and phononic crystals. Nevertheless, the crystal lattices achieved thus far with commodity colloids are largely limited to symmetric and densely packed structures, restricting their functionalities. To obtain non-close-packed crystals and the resulting complexity of the available structures, directional binding between “patchy” colloids has been pursued. However, the conventional “patchy” colloids have been restricted to micrometer-scale spherical particles or clusters. In this Mini-Review, we argue that the time has come to widen the scope of the colloidal palette and include particles made using DNA origami. By benefiting from its unprecedented ability to control nanoscale shapes and patch placement and incorporate various nanomaterials, DNA origami enables novel engineering of colloidal crystallization, particularly for photonic and phononic applications. This mini-review summarizes the recent progress on using DNA origami for colloidal crystallization, together with its challenges and opportunities.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Over the last three decades, colloidal crystallization has provided an easy-to-craft platform for mesoscale engineering of photonic and phononic crystals. Nevertheless, the crystal lattices achieved thus far with commodity colloids are largely limited to symmetric and densely packed structures, restricting their functionalities. To obtain non-close-packed crystals and the resulting complexity of the available structures, directional binding between “patchy” colloids has been pursued. However, the conventional “patchy” colloids have been restricted to micrometer-scale spherical particles or clusters. In this Mini-Review, we argue that the time has come to widen the scope of the colloidal palette and include particles made using DNA origami. By benefiting from its unprecedented ability to control nanoscale shapes and patch placement and incorporate various nanomaterials, DNA origami enables novel engineering of colloidal crystallization, particularly for photonic and phononic applications. This mini-review summarizes the recent progress on using DNA origami for colloidal crystallization, together with its challenges and opportunities.
1187.
K Barthelmi, T Amit, L Sigl, M Troue, T Klokkers, A Herrmann, T Taniguchi, K Watanabe, J J Finley, C Kastl, S Refaely-Abramson, A W Holleitner
Spectrally resolved far-field emission pattern of single photon emitters in $mathrmMomathrmS_2$ Journal Article
In: Physical Review Materials, vol. 9, no. 1, pp. 016201, 2025.
@article{nokey,
title = {Spectrally resolved far-field emission pattern of single photon emitters in $mathrmMomathrmS_2$},
author = {K Barthelmi and T Amit and L Sigl and M Troue and T Klokkers and A Herrmann and T Taniguchi and K Watanabe and J J Finley and C Kastl and S Refaely-Abramson and A W Holleitner},
url = {https://link.aps.org/doi/10.1103/PhysRevMaterials.9.016201},
doi = {10.1103/PhysRevMaterials.9.016201},
year = {2025},
date = {2025-01-08},
urldate = {2025-01-08},
journal = {Physical Review Materials},
volume = {9},
number = {1},
pages = {016201},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
1186.
A O Gudovannyy, J M Schäfer, O Gerdes, D Hildebrandt, G Mattersteig, M Pfeiffer, F Ortmann
Predicting 2D Crystal Packing in Thin Films of Small Molecule Organic Materials Journal Article
In: Advanced Functional Materials, vol. n/a, no. n/a, pp. 2421048, 2025, ISSN: 1616-301X.
@article{nokey,
title = {Predicting 2D Crystal Packing in Thin Films of Small Molecule Organic Materials},
author = {A O Gudovannyy and J M Sch\"{a}fer and O Gerdes and D Hildebrandt and G Mattersteig and M Pfeiffer and F Ortmann},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.202421048},
doi = {https://doi.org/10.1002/adfm.202421048},
issn = {1616-301X},
year = {2025},
date = {2025-01-07},
journal = {Advanced Functional Materials},
volume = {n/a},
number = {n/a},
pages = {2421048},
abstract = {Abstract The large variety of structural morphologies realized in organic semiconductors is a big challenge for the microscopic modeling of such systems. A global computational solution is still out of reach due to prevalent molecular flexibility. However, the specific case of crystalline thin films that exhibit surface alignment of molecular π-systems for optoelectronic applications of high technological relevance, seems to be a simpler task. This study proposes an approach for the structure prediction of two-dimensional (2D) molecular layers as precursors for the three-dimensional (3D) structure of deposited crystalline thin films. Based on grid search sampling for the layer's degrees of freedom, it requires only a small number of trial structures to find complex packing motifs of layered molecular materials. It facilitates parallel screening among multiple molecular conformers, which is usually very difficult and expensive, using the latest 3D-based prediction methods. The study researches theoretically and experimentally a set of known and newly crystallized compounds of evaporable flexible molecules with interesting optoelectronic properties, predicts their packing in 2D layers, and compares them with experimentally resolved crystal structures, obtaining very good agreement in the packing of these molecules within layers. The computational costs are estimated to be several orders of magnitude lower than with 3D methods.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract The large variety of structural morphologies realized in organic semiconductors is a big challenge for the microscopic modeling of such systems. A global computational solution is still out of reach due to prevalent molecular flexibility. However, the specific case of crystalline thin films that exhibit surface alignment of molecular π-systems for optoelectronic applications of high technological relevance, seems to be a simpler task. This study proposes an approach for the structure prediction of two-dimensional (2D) molecular layers as precursors for the three-dimensional (3D) structure of deposited crystalline thin films. Based on grid search sampling for the layer's degrees of freedom, it requires only a small number of trial structures to find complex packing motifs of layered molecular materials. It facilitates parallel screening among multiple molecular conformers, which is usually very difficult and expensive, using the latest 3D-based prediction methods. The study researches theoretically and experimentally a set of known and newly crystallized compounds of evaporable flexible molecules with interesting optoelectronic properties, predicts their packing in 2D layers, and compares them with experimentally resolved crystal structures, obtaining very good agreement in the packing of these molecules within layers. The computational costs are estimated to be several orders of magnitude lower than with 3D methods.
1185.
Z Feng, X Liu, T Tian, Z Zhu, R Jiang, J Li, Y Yuan, J Gong, G Gao, J Tong, Y Peng, S Bai, F Huang, X Xiao, P Müller-Buschbaum, Y-B Cheng, T Bu
In: Advanced Materials, vol. n/a, no. n/a, pp. 2412692, 2025, ISSN: 0935-9648.
@article{nokey,
title = {Buried Interface Modulation Using Self-Assembled Monolayer and Ionic Liquid Hybrids for High-Performance Perovskite and Perovskite/CuInGaSe2 Tandem Photovoltaics},
author = {Z Feng and X Liu and T Tian and Z Zhu and R Jiang and J Li and Y Yuan and J Gong and G Gao and J Tong and Y Peng and S Bai and F Huang and X Xiao and P M\"{u}ller-Buschbaum and Y-B Cheng and T Bu},
url = {https://doi.org/10.1002/adma.202412692},
doi = {https://doi.org/10.1002/adma.202412692},
issn = {0935-9648},
year = {2025},
date = {2025-01-06},
journal = {Advanced Materials},
volume = {n/a},
number = {n/a},
pages = {2412692},
abstract = {Abstract Effective modifications for the buried interface between self-assembled monolayers (SAMs) and perovskites are vital for the development of efficient, stable inverted perovskite solar cells (PSCs) and their tandem photovoltaics. Herein, an ionic-liquid-SAM hybrid strategy is developed to synergistically optimize the uniformity of SAMs and the crystallization of perovskites above. Specifically, an ionic liquid of 1-butyl-3-methyl-1H-imidazol-3-iumbis((trifluoromethyl)sulfonyl)amide (BMIMTFSI) is incorporated into the SAM solution, enabling reduced surface roughness, improved wettability, and a more evenly distributed surface potential of the SAM film. Leveraging this optimized substrate, a favorable growth of high-quality perovskite crystals is achieved. Furthermore, the introduced functional ions readily bond with the perovskites, effectively passivating undesirable cation or halide vacancies of the perovskite near the buried interface. Remarkably, high power conversion efficiencies (PCEs) of 25.68% and 22.53% are obtained for normal-bandgap (≈1.55 eV) and wide-bandgap (WBG) (≈1.66 eV) PSCs along with improved operational stability. Additionally, a champion PCE of 19.50% is achieved for semitransparent WBG PSCs, further delivering an impressive PCE of 28.34% for integrated four-terminal tandem photovoltaics when combined with CuInGaSe2 solar cells.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract Effective modifications for the buried interface between self-assembled monolayers (SAMs) and perovskites are vital for the development of efficient, stable inverted perovskite solar cells (PSCs) and their tandem photovoltaics. Herein, an ionic-liquid-SAM hybrid strategy is developed to synergistically optimize the uniformity of SAMs and the crystallization of perovskites above. Specifically, an ionic liquid of 1-butyl-3-methyl-1H-imidazol-3-iumbis((trifluoromethyl)sulfonyl)amide (BMIMTFSI) is incorporated into the SAM solution, enabling reduced surface roughness, improved wettability, and a more evenly distributed surface potential of the SAM film. Leveraging this optimized substrate, a favorable growth of high-quality perovskite crystals is achieved. Furthermore, the introduced functional ions readily bond with the perovskites, effectively passivating undesirable cation or halide vacancies of the perovskite near the buried interface. Remarkably, high power conversion efficiencies (PCEs) of 25.68% and 22.53% are obtained for normal-bandgap (≈1.55 eV) and wide-bandgap (WBG) (≈1.66 eV) PSCs along with improved operational stability. Additionally, a champion PCE of 19.50% is achieved for semitransparent WBG PSCs, further delivering an impressive PCE of 28.34% for integrated four-terminal tandem photovoltaics when combined with CuInGaSe2 solar cells.
1184.
S Chen, H Zhong, X Wang, G Pan, H Tang, F Fang, J Wu, W Wang, L Xu, J Tang, J Hao, K Zheng, D Wu, Z Tang, L Zhang, L Cao, P Müller-Buschbaum, K Wang, W Chen
Hybrid-Size Quantum Dots in Hole Transport Layer Depress Dark Current Density of Short-Wave Infrared Photodetectors Journal Article
In: ACS Photonics, 2025.
@article{nokey,
title = {Hybrid-Size Quantum Dots in Hole Transport Layer Depress Dark Current Density of Short-Wave Infrared Photodetectors},
author = {S Chen and H Zhong and X Wang and G Pan and H Tang and F Fang and J Wu and W Wang and L Xu and J Tang and J Hao and K Zheng and D Wu and Z Tang and L Zhang and L Cao and P M\"{u}ller-Buschbaum and K Wang and W Chen},
url = {https://doi.org/10.1021/acsphotonics.4c01864},
doi = {10.1021/acsphotonics.4c01864},
year = {2025},
date = {2025-01-02},
journal = {ACS Photonics},
abstract = {PbS quantum dots (QDs) are promising materials for low-cost short-wave infrared (SWIR) photodetection and imaging applications, owing to their unique optical properties and tunable bandgap. High-performance photodiodes rely on thiol-treated small PbS QDs as the hole transport layer (HTL) due to their suitable band alignment, but they face challenges such as crack formation, which increases dark currents. We develop a crack-free HTL by mixing small-size and large-size QDs. Grazing incidence small-angle X-ray scattering data confirms that the hybrid-size QD HTL is more homogeneous and denser than that made from monosize QDs. Photophysical studies show optimized charge carrier dynamics and energy transfer in the hybrid-size QDs, compared to monosize QDs. The devices based on the hybrid-size QD HTL exhibit a significantly reduced dark current density (392 nA/cm2). Additionally, they show high device performance, including a responsivity of 0.65 A/W, detectivity of 2.4 × 1012 Jones, and an external quantum efficiency of 65% in the SWIR region, paving the way for high-performance QD-based SWIR photodetectors.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
PbS quantum dots (QDs) are promising materials for low-cost short-wave infrared (SWIR) photodetection and imaging applications, owing to their unique optical properties and tunable bandgap. High-performance photodiodes rely on thiol-treated small PbS QDs as the hole transport layer (HTL) due to their suitable band alignment, but they face challenges such as crack formation, which increases dark currents. We develop a crack-free HTL by mixing small-size and large-size QDs. Grazing incidence small-angle X-ray scattering data confirms that the hybrid-size QD HTL is more homogeneous and denser than that made from monosize QDs. Photophysical studies show optimized charge carrier dynamics and energy transfer in the hybrid-size QDs, compared to monosize QDs. The devices based on the hybrid-size QD HTL exhibit a significantly reduced dark current density (392 nA/cm2). Additionally, they show high device performance, including a responsivity of 0.65 A/W, detectivity of 2.4 × 1012 Jones, and an external quantum efficiency of 65% in the SWIR region, paving the way for high-performance QD-based SWIR photodetectors.
1183.
L Spies, A Biewald, L Fuchs, K Merkel, M Righetto, Z Xu, R Guntermann, R Hooijer, L M Herz, F Ortmann, J Schneider, T Bein, A Hartschuh
Spatiotemporal Spectroscopy of Fast Excited-State Diffusion in 2D Covalent Organic Framework Thin Films Journal Article
In: Journal of the American Chemical Society, 2025, ISSN: 0002-7863.
@article{nokey,
title = {Spatiotemporal Spectroscopy of Fast Excited-State Diffusion in 2D Covalent Organic Framework Thin Films},
author = {L Spies and A Biewald and L Fuchs and K Merkel and M Righetto and Z Xu and R Guntermann and R Hooijer and L M Herz and F Ortmann and J Schneider and T Bein and A Hartschuh},
url = {https://doi.org/10.1021/jacs.4c13129},
doi = {10.1021/jacs.4c13129},
issn = {0002-7863},
year = {2025},
date = {2025-01-02},
journal = {Journal of the American Chemical Society},
abstract = {Covalent organic frameworks (COFs), crystalline and porous conjugated structures, are of great interest for sustainable energy applications. Organic building blocks in COFs with suitable electronic properties can feature strong optical absorption, whereas the extended crystalline network can establish a band structure enabling long-range coherent transport. This peculiar combination of both molecular and solid-state materials properties makes COFs an interesting platform to study and ultimately utilize photoexcited charge carrier diffusion. Herein, we investigated the charge carrier diffusion in a two-dimensional COF thin film generated through condensation of the building blocks benzodithiophene-dialdehyde (BDT) and N,N,N′,N′-tetra(4-aminophenyl)benzene-1,4-diamine (W). We visualized the spatiotemporal evolution of photogenerated excited states in the 2D WBDT COF thin film using remote-detected time-resolved PL measurements (RDTR PL). Combined with optical pump terahertz probe (OPTP) studies, we identified two diffusive species dominating the process at different time scales. Initially, short-lived free charge carriers diffuse almost temperature-independently before relaxing into bound states at a rate of 0.7 ps\textendash1. Supported by theoretical simulations, these long-lived bound states were identified as excitons. We directly accessed the lateral exciton diffusion within the oriented and crystalline film, revealing remarkably high diffusion coefficients of up to 4 cm2 s\textendash1 (200 K) and diffusion lengths of several hundreds of nanometers and across grain boundaries. Temperature-dependent exciton transport analysis showed contributions from both incoherent hopping and coherent band-like transport. In the transport model developed based on these findings, we discuss the complex impact of order and disorder on charge carrier diffusion within the WBDT COF thin film.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Covalent organic frameworks (COFs), crystalline and porous conjugated structures, are of great interest for sustainable energy applications. Organic building blocks in COFs with suitable electronic properties can feature strong optical absorption, whereas the extended crystalline network can establish a band structure enabling long-range coherent transport. This peculiar combination of both molecular and solid-state materials properties makes COFs an interesting platform to study and ultimately utilize photoexcited charge carrier diffusion. Herein, we investigated the charge carrier diffusion in a two-dimensional COF thin film generated through condensation of the building blocks benzodithiophene-dialdehyde (BDT) and N,N,N′,N′-tetra(4-aminophenyl)benzene-1,4-diamine (W). We visualized the spatiotemporal evolution of photogenerated excited states in the 2D WBDT COF thin film using remote-detected time-resolved PL measurements (RDTR PL). Combined with optical pump terahertz probe (OPTP) studies, we identified two diffusive species dominating the process at different time scales. Initially, short-lived free charge carriers diffuse almost temperature-independently before relaxing into bound states at a rate of 0.7 ps–1. Supported by theoretical simulations, these long-lived bound states were identified as excitons. We directly accessed the lateral exciton diffusion within the oriented and crystalline film, revealing remarkably high diffusion coefficients of up to 4 cm2 s–1 (200 K) and diffusion lengths of several hundreds of nanometers and across grain boundaries. Temperature-dependent exciton transport analysis showed contributions from both incoherent hopping and coherent band-like transport. In the transport model developed based on these findings, we discuss the complex impact of order and disorder on charge carrier diffusion within the WBDT COF thin film.
1182.
C Scheurer, K Reuter
Role of the human-in-the-loop in emerging self-driving laboratories for heterogeneous catalysis Journal Article
In: Nature Catalysis, vol. 8, no. 1, pp. 13-19, 2025, ISSN: 2520-1158.
@article{nokey,
title = {Role of the human-in-the-loop in emerging self-driving laboratories for heterogeneous catalysis},
author = {C Scheurer and K Reuter},
url = {https://doi.org/10.1038/s41929-024-01275-5},
doi = {10.1038/s41929-024-01275-5},
issn = {2520-1158},
year = {2025},
date = {2025-01-01},
journal = {Nature Catalysis},
volume = {8},
number = {1},
pages = {13-19},
abstract = {Self-driving laboratories (SDLs) represent a cutting-edge convergence of machine learning with laboratory automation. SDLs operate in active learning loops, in which a machine learning algorithm plans experiments that are subsequently executed by increasingly automated (robotic) modules. Here we present our view on emerging SDLs for accelerated discovery and process optimization in heterogeneous catalysis. We argue against the paradigm of full automation and the goal of keeping the human out of the loop. Based on analysis of the involved workflows, we instead conclude that crucial advances will come from establishing fast proxy experiments and re-engineering existing apparatuses and measurement protocols. Industrially relevant use cases will also require humans to be kept in the loop for continuous decision-making. In turn, active learning algorithms will have to be advanced that can flexibly deal with corresponding adaptations of the design space and varying information content and noise in the acquired data.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Self-driving laboratories (SDLs) represent a cutting-edge convergence of machine learning with laboratory automation. SDLs operate in active learning loops, in which a machine learning algorithm plans experiments that are subsequently executed by increasingly automated (robotic) modules. Here we present our view on emerging SDLs for accelerated discovery and process optimization in heterogeneous catalysis. We argue against the paradigm of full automation and the goal of keeping the human out of the loop. Based on analysis of the involved workflows, we instead conclude that crucial advances will come from establishing fast proxy experiments and re-engineering existing apparatuses and measurement protocols. Industrially relevant use cases will also require humans to be kept in the loop for continuous decision-making. In turn, active learning algorithms will have to be advanced that can flexibly deal with corresponding adaptations of the design space and varying information content and noise in the acquired data.
1181.
L Lafeta, S Hartmann, B Rosa, S Reitzenstein, L M Malard, A Hartschuh
Probing Noncentrosymmetric 2D Materials by Fourier Space Second Harmonic Imaging Journal Article
In: ACS Photonics, 2025.
@article{nokey,
title = {Probing Noncentrosymmetric 2D Materials by Fourier Space Second Harmonic Imaging},
author = {L Lafeta and S Hartmann and B Rosa and S Reitzenstein and L M Malard and A Hartschuh},
url = {https://doi.org/10.1021/acsphotonics.4c01724},
doi = {10.1021/acsphotonics.4c01724},
year = {2025},
date = {2025-01-01},
journal = {ACS Photonics},
abstract = {Second-harmonic generation (SHG) has been established as a powerful tool for probing noncentrosymmetric materials. In the typical implementation, the SHG intensity is detected while rotating the polarization of the incident laser field and of the second harmonic relative to the sample. Although effective, this approach can be time-consuming and laborious. Here, we present a novel experimental approach for directly determining the symmetry and crystal orientation of noncentrosymmetric 2D materials. This approach involves capturing SH images generated by tightly focused laser beams in Fourier space and exploits the material’s symmetry and SHG’s coherent nature. For a Gaussian laser beam, the crystal orientation of the 2D material can be derived from the ellipticity of the observed SHG patterns, whereas for an azimuthally polarized laser beam, the detected SHG pattern directly reveals the crystal lattice together with its orientation. A microscopic model that treats SHG as a coherent superposition of fields radiated by dipolar emitters within the laser-illuminated area and that considers the symmetry of the χ(2)-tensor quantitatively describes the detected patterns. The approach presented provides a fast and precise tool for determining crystal symmetry and orientation and will be applicable to materials with broken inversion symmetry.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Second-harmonic generation (SHG) has been established as a powerful tool for probing noncentrosymmetric materials. In the typical implementation, the SHG intensity is detected while rotating the polarization of the incident laser field and of the second harmonic relative to the sample. Although effective, this approach can be time-consuming and laborious. Here, we present a novel experimental approach for directly determining the symmetry and crystal orientation of noncentrosymmetric 2D materials. This approach involves capturing SH images generated by tightly focused laser beams in Fourier space and exploits the material’s symmetry and SHG’s coherent nature. For a Gaussian laser beam, the crystal orientation of the 2D material can be derived from the ellipticity of the observed SHG patterns, whereas for an azimuthally polarized laser beam, the detected SHG pattern directly reveals the crystal lattice together with its orientation. A microscopic model that treats SHG as a coherent superposition of fields radiated by dipolar emitters within the laser-illuminated area and that considers the symmetry of the χ(2)-tensor quantitatively describes the detected patterns. The approach presented provides a fast and precise tool for determining crystal symmetry and orientation and will be applicable to materials with broken inversion symmetry.
1180.
A F Harper, T Huss, S S Köcher, C Scheurer
Tracking Li atoms in real-time with ultra-fast NMR simulations Journal Article
In: Faraday Discussions, vol. 255, no. 0, pp. 411-428, 2025, ISSN: 1359-6640.
@article{nokey,
title = {Tracking Li atoms in real-time with ultra-fast NMR simulations},
author = {A F Harper and T Huss and S S K\"{o}cher and C Scheurer},
url = {http://dx.doi.org/10.1039/D4FD00074A},
doi = {10.1039/D4FD00074A},
issn = {1359-6640},
year = {2025},
date = {2025-01-01},
journal = {Faraday Discussions},
volume = {255},
number = {0},
pages = {411-428},
abstract = {We present for the first time a multiscale machine learning approach to jointly simulate atomic structure and dynamics with the corresponding solid state Nuclear Magnetic Resonance (ssNMR) observables. We study the use-case of spin-alignment echo (SAE) NMR for exploring Li-ion diffusion within the solid state electrolyte material Li3PS4 (LPS) by calculating quadrupolar frequencies of 7Li. SAE NMR probes long-range dynamics down to microsecond-timescale hopping processes. Therefore only a few machine learning force field schemes are able to capture the time- and length scales required for accurate comparison with experimental results. By using a new class of machine learning interatomic potentials, known as ultra-fast potentials (UFPs), we are able to efficiently access timescales beyond the microsecond regime. In tandem, we have developed a machine learning model for predicting the full 7Li electric field gradient (EFG) tensors in LPS. By combining the long timescale trajectories from the UFP with our model for 7Li EFG tensors, we are able to extract the autocorrelation function (ACF) for 7Li quadrupolar frequencies during Li diffusion. We extract the decay constants from the ACF for both crystalline β-LPS and amorphous LPS, and find that the predicted Li hopping rates are on the same order of magnitude as those predicted from the Li dynamics. This demonstrates the potential for machine learning to finally make predictions on experimentally relevant timescales and temperatures, and opens a new avenue of NMR crystallography: using machine learning dynamical NMR simulations for accessing polycrystalline and glass ceramic materials.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We present for the first time a multiscale machine learning approach to jointly simulate atomic structure and dynamics with the corresponding solid state Nuclear Magnetic Resonance (ssNMR) observables. We study the use-case of spin-alignment echo (SAE) NMR for exploring Li-ion diffusion within the solid state electrolyte material Li3PS4 (LPS) by calculating quadrupolar frequencies of 7Li. SAE NMR probes long-range dynamics down to microsecond-timescale hopping processes. Therefore only a few machine learning force field schemes are able to capture the time- and length scales required for accurate comparison with experimental results. By using a new class of machine learning interatomic potentials, known as ultra-fast potentials (UFPs), we are able to efficiently access timescales beyond the microsecond regime. In tandem, we have developed a machine learning model for predicting the full 7Li electric field gradient (EFG) tensors in LPS. By combining the long timescale trajectories from the UFP with our model for 7Li EFG tensors, we are able to extract the autocorrelation function (ACF) for 7Li quadrupolar frequencies during Li diffusion. We extract the decay constants from the ACF for both crystalline β-LPS and amorphous LPS, and find that the predicted Li hopping rates are on the same order of magnitude as those predicted from the Li dynamics. This demonstrates the potential for machine learning to finally make predictions on experimentally relevant timescales and temperatures, and opens a new avenue of NMR crystallography: using machine learning dynamical NMR simulations for accessing polycrystalline and glass ceramic materials.
1179.
H Türk, X Q Tran, P König, A Hammud, V Vibhu, F-P Schmidt, D Berger, S Selve, V Roddatis, D Abou-Ras, F Girgsdies, Y-T Chan, T Götsch, H Ali, I C Vinke, L G J De Haart, M Lehmann, A Knop-Gericke, K Reuter, R-A Eichel, C Scheurer, T Lunkenbein
Boon and Bane of Local Solid State Chemistry on the Performance of LSM-Based Solid Oxide Electrolysis Cells Journal Article
In: Advanced Energy Materials, vol. n/a, no. n/a, pp. 2405599, 2024, ISSN: 1614-6832.
@article{nokey,
title = {Boon and Bane of Local Solid State Chemistry on the Performance of LSM-Based Solid Oxide Electrolysis Cells},
author = {H T\"{u}rk and X Q Tran and P K\"{o}nig and A Hammud and V Vibhu and F-P Schmidt and D Berger and S Selve and V Roddatis and D Abou-Ras and F Girgsdies and Y-T Chan and T G\"{o}tsch and H Ali and I C Vinke and L G J De Haart and M Lehmann and A Knop-Gericke and K Reuter and R-A Eichel and C Scheurer and T Lunkenbein},
url = {https://doi.org/10.1002/aenm.202405599},
doi = {https://doi.org/10.1002/aenm.202405599},
issn = {1614-6832},
year = {2024},
date = {2024-12-31},
urldate = {2024-12-31},
journal = {Advanced Energy Materials},
volume = {n/a},
number = {n/a},
pages = {2405599},
abstract = {Abstract High-temperature solid oxide cells are highly efficient energy converters. However, their lifetime is limited by rapid deactivation. Little is known about the local, atomic scale transformation that drive this degradation. Here, reaction-induced changes are unraveled at the atomic scale of a solid oxide electrolysis cell (SOEC) operated for 550 h by combining high-resolution scanning transmission electron microscopy with first-principles and force-field-based atomistic simulations. We focus on the structural evolution of lanthanum strontium manganite (LSM)/yttria-stabilized zirconia (YSZ) regions and the corresponding solid?solid interface. It is found that the strong inter-diffusion of cations leads to the additional formation and growth of a multitude of localized structures such as a solid solution of La/Mn, nano-domains of secondary structures or antisite defects in the YSZ, as well as a mixed ion and electron conduction region in the LSM and complexion. These local structures can be likewise beneficial or detrimental to the performance, by either increasing the catalytically active area or by limiting the supply of reactants. The work provides unprecedented atomistic insights into the influence of local solid-state chemistry on the functioning of SOECs and deepens the understanding of the degradation mechanism in SOECs, paving the way towards nanoscopic rational interface design for more efficient and durable cells.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract High-temperature solid oxide cells are highly efficient energy converters. However, their lifetime is limited by rapid deactivation. Little is known about the local, atomic scale transformation that drive this degradation. Here, reaction-induced changes are unraveled at the atomic scale of a solid oxide electrolysis cell (SOEC) operated for 550 h by combining high-resolution scanning transmission electron microscopy with first-principles and force-field-based atomistic simulations. We focus on the structural evolution of lanthanum strontium manganite (LSM)/yttria-stabilized zirconia (YSZ) regions and the corresponding solid?solid interface. It is found that the strong inter-diffusion of cations leads to the additional formation and growth of a multitude of localized structures such as a solid solution of La/Mn, nano-domains of secondary structures or antisite defects in the YSZ, as well as a mixed ion and electron conduction region in the LSM and complexion. These local structures can be likewise beneficial or detrimental to the performance, by either increasing the catalytically active area or by limiting the supply of reactants. The work provides unprecedented atomistic insights into the influence of local solid-state chemistry on the functioning of SOECs and deepens the understanding of the degradation mechanism in SOECs, paving the way towards nanoscopic rational interface design for more efficient and durable cells.
1178.
K Nisi, J C Thomas, S Levashov, E Mitterreiter, T Taniguchi, K Watanabe, S Aloni, T R Kuykendall, J Eichhorn, A W Holleitner, A Weber-Bargioni, C Kastl
Scanning probe spectroscopy of sulfur vacancies and MoS2 monolayers in side-contacted van der Waals heterostructures Journal Article
In: 2D Materials, vol. 12, no. 1, pp. 015023, 2024, ISSN: 2053-1583.
@article{nokey,
title = {Scanning probe spectroscopy of sulfur vacancies and MoS2 monolayers in side-contacted van der Waals heterostructures},
author = {K Nisi and J C Thomas and S Levashov and E Mitterreiter and T Taniguchi and K Watanabe and S Aloni and T R Kuykendall and J Eichhorn and A W Holleitner and A Weber-Bargioni and C Kastl},
url = {https://dx.doi.org/10.1088/2053-1583/ada046},
doi = {10.1088/2053-1583/ada046},
issn = {2053-1583},
year = {2024},
date = {2024-12-30},
journal = {2D Materials},
volume = {12},
number = {1},
pages = {015023},
abstract = {We investigate the interplay between vertical tunneling and lateral transport phenomena in electrically contacted van der Waals heterostructures made from monolayer MoS2, hBN, and graphene. We compare data taken by low-temperature scanning tunneling spectroscopy to results from room-temperature conductive atomic force spectroscopy on monolayer MoS2 with sulfur vacancies and with varying hBN layers. We show that for thick hBN barrier layers, where tunneling currents into the conductive substrate are suppressed, a side-contact still enables addressing the defect states in the scanning tunneling microscopy via the lateral current flow. Few-layer hBN realizes an intermediate regime in which the competition between vertical tunneling and lateral transport needs to be considered. The latter is relevant for device structures with both a thin tunneling barrier and a side-contact to the semiconducting layers.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We investigate the interplay between vertical tunneling and lateral transport phenomena in electrically contacted van der Waals heterostructures made from monolayer MoS2, hBN, and graphene. We compare data taken by low-temperature scanning tunneling spectroscopy to results from room-temperature conductive atomic force spectroscopy on monolayer MoS2 with sulfur vacancies and with varying hBN layers. We show that for thick hBN barrier layers, where tunneling currents into the conductive substrate are suppressed, a side-contact still enables addressing the defect states in the scanning tunneling microscopy via the lateral current flow. Few-layer hBN realizes an intermediate regime in which the competition between vertical tunneling and lateral transport needs to be considered. The latter is relevant for device structures with both a thin tunneling barrier and a side-contact to the semiconducting layers.
1177.
Y Zhu, H Duan, C G Gruber, W Qu, H Zhang, Z Wang, J Zhong, X Zhang, L Han, D Cheng, D D Medina, E Cortés, D Zhang
Boosting Electrocatalytic Nitrate Reduction through Enhanced Mass Transfer in Cu-Bipyridine 2D Covalent Organic Framework Films Journal Article
In: Angewandte Chemie International Edition, vol. n/a, no. n/a, pp. e202421821, 2024, ISSN: 1433-7851.
@article{nokey,
title = {Boosting Electrocatalytic Nitrate Reduction through Enhanced Mass Transfer in Cu-Bipyridine 2D Covalent Organic Framework Films},
author = {Y Zhu and H Duan and C G Gruber and W Qu and H Zhang and Z Wang and J Zhong and X Zhang and L Han and D Cheng and D D Medina and E Cort\'{e}s and D Zhang},
url = {https://doi.org/10.1002/anie.202421821},
doi = {https://doi.org/10.1002/anie.202421821},
issn = {1433-7851},
year = {2024},
date = {2024-12-24},
journal = {Angewandte Chemie International Edition},
volume = {n/a},
number = {n/a},
pages = {e202421821},
abstract = {Abstract Electrocatalytic nitrate reduction (NO3RR) is a promising method for pollutant removal and ammonia synthesis and involves the transfer of eight electrons and nine protons. As such, the rational design of catalytic interfaces with enhanced mass transfer is crucial for achieving high ammonia yield rates and Faradaic efficiency (FE). In this work, we incorporated a Cu-bipyridine catalytic interface and fabricated crystalline 2D covalent organic framework films with significantly exposed catalytic sites, leading to improved FE and ammonia yield (FE=92.7?%, NH3 yield rate=14.9?mg???h?1cm?2 in 0.5?M nitrate) compared to bulk catalysts and outperforming most reported NO3RR electrocatalysts. The film-like morphology enhances mass transfer across the Cu-bipyridine interface, resulting in superior catalytic performance. We confirmed the reaction pathway and mechanism through in situ characterizations and theoretical calculations. The Cu sites act as primary centers for adsorption and activation, while the bipyridine sites facilitate water adsorption and dissociation, supplying sufficient H* and accelerating proton-coupled electron transfer kinetics. This study provides a viable strategy to enhance mass transfer at the catalytic interface through rational morphology control, boosting the intrinsic activity of catalysts in the NO3RR process.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract Electrocatalytic nitrate reduction (NO3RR) is a promising method for pollutant removal and ammonia synthesis and involves the transfer of eight electrons and nine protons. As such, the rational design of catalytic interfaces with enhanced mass transfer is crucial for achieving high ammonia yield rates and Faradaic efficiency (FE). In this work, we incorporated a Cu-bipyridine catalytic interface and fabricated crystalline 2D covalent organic framework films with significantly exposed catalytic sites, leading to improved FE and ammonia yield (FE=92.7?%, NH3 yield rate=14.9?mg???h?1cm?2 in 0.5?M nitrate) compared to bulk catalysts and outperforming most reported NO3RR electrocatalysts. The film-like morphology enhances mass transfer across the Cu-bipyridine interface, resulting in superior catalytic performance. We confirmed the reaction pathway and mechanism through in situ characterizations and theoretical calculations. The Cu sites act as primary centers for adsorption and activation, while the bipyridine sites facilitate water adsorption and dissociation, supplying sufficient H* and accelerating proton-coupled electron transfer kinetics. This study provides a viable strategy to enhance mass transfer at the catalytic interface through rational morphology control, boosting the intrinsic activity of catalysts in the NO3RR process.
1176.
J Zhang, Z Li, X Jiang, L Xie, G Pan, A Buyan-Arivjikh, T Baier, S Tu, L Li, M Schwartzkopf, S K Vayalil, S V Roth, Z Ge, P Müller-Buschbaum
In: Advanced Energy Materials, vol. n/a, no. n/a, pp. 2404724, 2024, ISSN: 1614-6832.
@article{nokey,
title = {Revealing the Effect of Solvent Additive Selectivity on Morphology and Formation Kinetics in Printed Non-fullerene Organic Solar Cells at Ambient Conditions},
author = {J Zhang and Z Li and X Jiang and L Xie and G Pan and A Buyan-Arivjikh and T Baier and S Tu and L Li and M Schwartzkopf and S K Vayalil and S V Roth and Z Ge and P M\"{u}ller-Buschbaum},
url = {https://doi.org/10.1002/aenm.202404724},
doi = {https://doi.org/10.1002/aenm.202404724},
issn = {1614-6832},
year = {2024},
date = {2024-12-23},
journal = {Advanced Energy Materials},
volume = {n/a},
number = {n/a},
pages = {2404724},
abstract = {Abstract Solvent additives enable the efficient modification of the morphology to improve the power conversion efficiency (PCE) of organic solar cells. However, the impact of solvent additive selectivity on the film morphology and formation kinetics is still unclarified. Herein, this work investigates two solvent additives, 1-chloronaphthalene (1-CN) and tetralin, characterized by their varying selectivity for the polymer donor (PBDB-T-2F) and the non-fullerene small molecule acceptor (BTP-C3-4F). Specifically, 1-CN exhibits superior solubility for BTP-C3-4F over PBDB-T-2F, whereas tetralin shows the opposite trend. The blend films with and without solvent additives are fabricated with the slot-die coating at ambient conditions. Both solvent additives can promote larger phase separation and increase the size of crystals of the selectively dissolved component. In situ grazing-incidence wide-angle X-ray scattering and UV?vis absorption spectra during printing unveil two distinct kinetic processes induced by 1-CN and tetralin, leading to large-sized crystals. 1-CN can prolong the liquid-solid phase separation to provide sufficient time for the BTP-C3-4F crystal growth but suppress the crystal growth of PBDB-T-2F. Tetralin can swell PBDB-T-2F and break down BTP-C3-4F crystals at the same time. Upon thermal annealing, the oversized crystals triggered by both solvent additives can be optimized to an appropriate size, resulting in an enhanced PCE.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract Solvent additives enable the efficient modification of the morphology to improve the power conversion efficiency (PCE) of organic solar cells. However, the impact of solvent additive selectivity on the film morphology and formation kinetics is still unclarified. Herein, this work investigates two solvent additives, 1-chloronaphthalene (1-CN) and tetralin, characterized by their varying selectivity for the polymer donor (PBDB-T-2F) and the non-fullerene small molecule acceptor (BTP-C3-4F). Specifically, 1-CN exhibits superior solubility for BTP-C3-4F over PBDB-T-2F, whereas tetralin shows the opposite trend. The blend films with and without solvent additives are fabricated with the slot-die coating at ambient conditions. Both solvent additives can promote larger phase separation and increase the size of crystals of the selectively dissolved component. In situ grazing-incidence wide-angle X-ray scattering and UV?vis absorption spectra during printing unveil two distinct kinetic processes induced by 1-CN and tetralin, leading to large-sized crystals. 1-CN can prolong the liquid-solid phase separation to provide sufficient time for the BTP-C3-4F crystal growth but suppress the crystal growth of PBDB-T-2F. Tetralin can swell PBDB-T-2F and break down BTP-C3-4F crystals at the same time. Upon thermal annealing, the oversized crystals triggered by both solvent additives can be optimized to an appropriate size, resulting in an enhanced PCE.
1175.
P Moser, L M Wolz, A Henning, A Thurn, M Kuhl, P Ji, P Soubelet, M Schalk, J Eichhorn, I D Sharp, A V Stier, J J Finley
Atomically Flat Dielectric Patterns for Bandgap Engineering and Lateral Junction Formation in MoSe2 Monolayers Journal Article
In: Advanced Functional Materials, vol. n/a, no. n/a, pp. 2418528, 2024, ISSN: 1616-301X.
@article{nokey,
title = {Atomically Flat Dielectric Patterns for Bandgap Engineering and Lateral Junction Formation in MoSe2 Monolayers},
author = {P Moser and L M Wolz and A Henning and A Thurn and M Kuhl and P Ji and P Soubelet and M Schalk and J Eichhorn and I D Sharp and A V Stier and J J Finley},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.202418528},
doi = {https://doi.org/10.1002/adfm.202418528},
issn = {1616-301X},
year = {2024},
date = {2024-12-23},
journal = {Advanced Functional Materials},
volume = {n/a},
number = {n/a},
pages = {2418528},
abstract = {Abstract Combining a precise sputter etching method with subsequent AlOx growth within an atomic layer deposition chamber enables the fabrication of atomically flat lateral patterns of SiO2 and AlOx. The transfer of MoSe2 monolayers onto these dielectrically modulated substrates results in the formation of lateral heterojunctions due to the interaction with alternating regions of SiO2 and AlOx, with the flat substrate topography leading to minimal strain across the junction. Kelvin probe force microscopy measurements show significant variations in the contact potential difference (CPD) across the interface, with AlOx regions inducing a 230 mV increase in CPD. Photoluminescence spectroscopy reveals shifts in spectral weight of neutral and charged exciton species across the different dielectric regions. On the AlOx side, the Fermi energy moves closer to the conduction band, leading to a higher trion-to-exciton ratio, indicating a bandgap shift consistent with CPD changes. In addition, transient reflection spectroscopy highlights the influence of the dielectric environment on carrier dynamics, with the SiO2 side exhibiting rapid carrier decay typical of neutral exciton recombination. In contrast, the AlOx side shows slower, mixed decay behavior consistent with conversion of trions back into excitons. These results demonstrate how dielectric substrate engineering can tune 2D materials, allowing scalable fabrication of advanced junctions for novel (opto)electronics applications.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract Combining a precise sputter etching method with subsequent AlOx growth within an atomic layer deposition chamber enables the fabrication of atomically flat lateral patterns of SiO2 and AlOx. The transfer of MoSe2 monolayers onto these dielectrically modulated substrates results in the formation of lateral heterojunctions due to the interaction with alternating regions of SiO2 and AlOx, with the flat substrate topography leading to minimal strain across the junction. Kelvin probe force microscopy measurements show significant variations in the contact potential difference (CPD) across the interface, with AlOx regions inducing a 230 mV increase in CPD. Photoluminescence spectroscopy reveals shifts in spectral weight of neutral and charged exciton species across the different dielectric regions. On the AlOx side, the Fermi energy moves closer to the conduction band, leading to a higher trion-to-exciton ratio, indicating a bandgap shift consistent with CPD changes. In addition, transient reflection spectroscopy highlights the influence of the dielectric environment on carrier dynamics, with the SiO2 side exhibiting rapid carrier decay typical of neutral exciton recombination. In contrast, the AlOx side shows slower, mixed decay behavior consistent with conversion of trions back into excitons. These results demonstrate how dielectric substrate engineering can tune 2D materials, allowing scalable fabrication of advanced junctions for novel (opto)electronics applications.
1174.
G Pan, S Yin, L F Huber, Z Li, T Tian, L V Spanier, H Zhong, T Guan, C R Ehgartner, N Hüsing, M Schwartzkopf, S V Roth, P Müller-Buschbaum
UV Irradiation as a Versatile Low-Temperature Strategy for Fabricating Templated Mesoporous Titania Films Journal Article
In: Small, vol. n/a, no. n/a, pp. 2409856, 2024, ISSN: 1613-6810.
@article{nokey,
title = {UV Irradiation as a Versatile Low-Temperature Strategy for Fabricating Templated Mesoporous Titania Films},
author = {G Pan and S Yin and L F Huber and Z Li and T Tian and L V Spanier and H Zhong and T Guan and C R Ehgartner and N H\"{u}sing and M Schwartzkopf and S V Roth and P M\"{u}ller-Buschbaum},
url = {https://doi.org/10.1002/smll.202409856},
doi = {https://doi.org/10.1002/smll.202409856},
issn = {1613-6810},
year = {2024},
date = {2024-12-17},
journal = {Small},
volume = {n/a},
number = {n/a},
pages = {2409856},
abstract = {Abstract Mesoporous titania thin films offer promising applications in sensors, batteries, and solar cells. The traditional soft templating methods rely on high-temperature calcination, which is energy-intensive, incompatible with thermosensitive flexible substrates, and destructive for titania structures. This work demonstrates UV irradiation as a versatile low-temperature and energy-saving alternative for mesoporous crystalline titania fabrication. Grazing incidence wide-angle X-ray scattering analysis reveals a three-stage crystallization process with increasing UV irradiation time supported by photoluminescence data. UV-irradiation-derived samples exhibit crystallinity and crystal size comparable to that of calcination. Integration with block copolymer templated sol?gel synthesis enables the creation of various morphologies, including cylindrical, ordered spherical, and hybrid structures. Characterizations via scanning electron microscopy and grazing incidence small-angle X-ray scattering confirm the homogeneity of morphology in the resulting films. The resulting films maintain similar optical properties despite morphological differences, as demonstrated by photoluminescence and UV?vis measurements. The versatility of UV irradiation extends to different titanium precursors, underscoring it as a flexible and efficient method for mesoporous titania thin film fabrication at low temperatures.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract Mesoporous titania thin films offer promising applications in sensors, batteries, and solar cells. The traditional soft templating methods rely on high-temperature calcination, which is energy-intensive, incompatible with thermosensitive flexible substrates, and destructive for titania structures. This work demonstrates UV irradiation as a versatile low-temperature and energy-saving alternative for mesoporous crystalline titania fabrication. Grazing incidence wide-angle X-ray scattering analysis reveals a three-stage crystallization process with increasing UV irradiation time supported by photoluminescence data. UV-irradiation-derived samples exhibit crystallinity and crystal size comparable to that of calcination. Integration with block copolymer templated sol?gel synthesis enables the creation of various morphologies, including cylindrical, ordered spherical, and hybrid structures. Characterizations via scanning electron microscopy and grazing incidence small-angle X-ray scattering confirm the homogeneity of morphology in the resulting films. The resulting films maintain similar optical properties despite morphological differences, as demonstrated by photoluminescence and UV?vis measurements. The versatility of UV irradiation extends to different titanium precursors, underscoring it as a flexible and efficient method for mesoporous titania thin film fabrication at low temperatures.
1173.
R Zhang, Y Liu, P Ding, J Huang, M Dierolf, S D Kelly, X Qiu, Y Chen, M Z Hussain, W Li, H Bunzen, K Achterhold, F Pfeiffer, I D Sharp, J Warnan, R A Fischer
Engineering a Cu-Pd Paddle-Wheel Metal–Organic Framework for Selective CO2 Electroreduction Journal Article
In: Angewandte Chemie International Edition, vol. 63, no. 51, pp. e202414600, 2024, ISSN: 1433-7851.
@article{nokey,
title = {Engineering a Cu-Pd Paddle-Wheel Metal\textendashOrganic Framework for Selective CO2 Electroreduction},
author = {R Zhang and Y Liu and P Ding and J Huang and M Dierolf and S D Kelly and X Qiu and Y Chen and M Z Hussain and W Li and H Bunzen and K Achterhold and F Pfeiffer and I D Sharp and J Warnan and R A Fischer},
url = {https://doi.org/10.1002/anie.202414600},
doi = {https://doi.org/10.1002/anie.202414600},
issn = {1433-7851},
year = {2024},
date = {2024-12-16},
journal = {Angewandte Chemie International Edition},
volume = {63},
number = {51},
pages = {e202414600},
abstract = {Abstract Optimizing the binding energy between the intermediate and the active site is a key factor for tuning catalytic product selectivity and activity in the electrochemical carbon dioxide reduction reaction. Copper active sites are known to reduce CO2 to hydrocarbons and oxygenates, but suffer from poor product selectivity due to the moderate binding energies of several of the reaction intermediates. Here, we report an ion exchange strategy to construct Cu?Pd paddle wheel dimers within Cu-based metal?organic frameworks (MOFs), [Cu3-xPdx(BTC)2] (BTC=benzentricarboxylate), without altering the overall MOF structural properties. Compared to the pristine Cu MOF ([Cu3(BTC)2], HKUST-1), the Cu?Pd MOF shifts CO2 electroreduction products from diverse chemical species to selective CO generation. In situ X-ray absorption fine structure analysis of the catalyst oxidation state and local geometry, combined with theoretical calculations, reveal that the incorporation of Pd within the Cu?Pd paddle wheel node structure of the MOF promotes adsorption of the key intermediate COOH* at the Cu site. This permits CO-selective catalytic mechanisms and thus advances our understanding of the interplay between structure and activity toward electrochemical CO2 reduction using molecular catalysts.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract Optimizing the binding energy between the intermediate and the active site is a key factor for tuning catalytic product selectivity and activity in the electrochemical carbon dioxide reduction reaction. Copper active sites are known to reduce CO2 to hydrocarbons and oxygenates, but suffer from poor product selectivity due to the moderate binding energies of several of the reaction intermediates. Here, we report an ion exchange strategy to construct Cu?Pd paddle wheel dimers within Cu-based metal?organic frameworks (MOFs), [Cu3-xPdx(BTC)2] (BTC=benzentricarboxylate), without altering the overall MOF structural properties. Compared to the pristine Cu MOF ([Cu3(BTC)2], HKUST-1), the Cu?Pd MOF shifts CO2 electroreduction products from diverse chemical species to selective CO generation. In situ X-ray absorption fine structure analysis of the catalyst oxidation state and local geometry, combined with theoretical calculations, reveal that the incorporation of Pd within the Cu?Pd paddle wheel node structure of the MOF promotes adsorption of the key intermediate COOH* at the Cu site. This permits CO-selective catalytic mechanisms and thus advances our understanding of the interplay between structure and activity toward electrochemical CO2 reduction using molecular catalysts.
1172.
E Sirotti, S Böhm, G Grötzner, M Christis, L I Wagner, L Wolz, F Munnik, J Eichhorn, M Stutzmann, V Streibel, I D Sharp
Amorphous nitride semiconductors with highly tunable optical and electronic properties: the benefits of disorder in Ca–Zn–N thin films Journal Article
In: Materials Horizons, 2024, ISSN: 2051-6347.
@article{nokey,
title = {Amorphous nitride semiconductors with highly tunable optical and electronic properties: the benefits of disorder in Ca\textendashZn\textendashN thin films},
author = {E Sirotti and S B\"{o}hm and G Gr\"{o}tzner and M Christis and L I Wagner and L Wolz and F Munnik and J Eichhorn and M Stutzmann and V Streibel and I D Sharp},
url = {http://dx.doi.org/10.1039/D4MH01525H},
doi = {10.1039/D4MH01525H},
issn = {2051-6347},
year = {2024},
date = {2024-12-16},
journal = {Materials Horizons},
abstract = {Semiconducting ternary nitrides are a promising class of materials that have received increasing attention in recent years, but often show high free electron concentrations due to the low defect formation energies of nitrogen vacancies and substitutional oxygen, leading to degenerate n-type doping. To achieve non-degenerate behavior, we now investigate a family of amorphous calcium\textendashzinc nitride (Ca\textendashZn\textendashN) thin films. By adjusting the metal cation ratios, we demonstrate band gap tunability between 1.4 and 2.0 eV and control over the charge carrier concentration across six orders of magnitude, all while maintaining high mobilities between 5 and 70 cm2 V−1 s−1. The combination of favorable electronic properties, low synthesis temperatures, and earth-abundant elements makes amorphous Ca\textendashZn\textendashN highly promising for future sustainable electronics. Moreover, the successful synthesis of such materials, as well as their broad optical and electrical tunability, paves the way for a new class of tailored functional materials: amorphous nitride semiconductors \textendash ANSs.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Semiconducting ternary nitrides are a promising class of materials that have received increasing attention in recent years, but often show high free electron concentrations due to the low defect formation energies of nitrogen vacancies and substitutional oxygen, leading to degenerate n-type doping. To achieve non-degenerate behavior, we now investigate a family of amorphous calcium–zinc nitride (Ca–Zn–N) thin films. By adjusting the metal cation ratios, we demonstrate band gap tunability between 1.4 and 2.0 eV and control over the charge carrier concentration across six orders of magnitude, all while maintaining high mobilities between 5 and 70 cm2 V−1 s−1. The combination of favorable electronic properties, low synthesis temperatures, and earth-abundant elements makes amorphous Ca–Zn–N highly promising for future sustainable electronics. Moreover, the successful synthesis of such materials, as well as their broad optical and electrical tunability, paves the way for a new class of tailored functional materials: amorphous nitride semiconductors – ANSs.
1171.
X Jiang, J Zeng, K Sun, Z Li, Z Xu, G Pan, R Guo, S Liang, Y Bulut, B Sochor, M Schwartzkopf, K A Reck, T Strunskus, F Faupel, S V Roth, B Xu, P Müller-Buschbaum
Sputter-deposited TiOx thin film as a buried interface modification layer for efficient and stable perovskite solar cells Journal Article
In: Nano Energy, vol. 132, pp. 110360, 2024, ISSN: 2211-2855.
@article{nokey,
title = {Sputter-deposited TiOx thin film as a buried interface modification layer for efficient and stable perovskite solar cells},
author = {X Jiang and J Zeng and K Sun and Z Li and Z Xu and G Pan and R Guo and S Liang and Y Bulut and B Sochor and M Schwartzkopf and K A Reck and T Strunskus and F Faupel and S V Roth and B Xu and P M\"{u}ller-Buschbaum},
url = {https://www.sciencedirect.com/science/article/pii/S2211285524011121},
doi = {https://doi.org/10.1016/j.nanoen.2024.110360},
issn = {2211-2855},
year = {2024},
date = {2024-12-15},
journal = {Nano Energy},
volume = {132},
pages = {110360},
abstract = {Despite perovskite solar cells (PSCs) based on a SnO2 hole-blocking layer (HBL) are achieving excellent performance, the non-perfect buried interface between the SnO2 HBL and the perovskite layer is still an obstacle in achieving further improvement in power conversion efficiency (PCE) and stability. The poor morphology with numerous defects and the energy level mismatch at the buried interface constrain the open circuit voltage and cause instability. Herein, a sputter-deposited TiOx thin film is used as a buried interface modification layer to address the aforementioned issues. Utilizing in situ grazing-incidence small-angle X-ray scattering (GISAXS) during the sputter deposition, we monitor and unveil the growth process of the TiOx thin film, identifying a 10 nm thickness optimum. The defects at the buried interface are passivated through tuning the growth, leading to a suppressed non-radiative recombination and improved PCE (from 22.19 % to 23.93 %). The evolution of the device performance and the degradation process of PSCs using operando grazing-incidence wide-angle X-ray scattering (GIWAXS) under the protocol ISOS-L-1I explains the enhanced stability introduced by the buried interface modification via a sputter-deposited TiOx thin layer. The perovskite decomposition process and the detrimental formation of PbI2 are both slowed down by the TiOx thin layer.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Despite perovskite solar cells (PSCs) based on a SnO2 hole-blocking layer (HBL) are achieving excellent performance, the non-perfect buried interface between the SnO2 HBL and the perovskite layer is still an obstacle in achieving further improvement in power conversion efficiency (PCE) and stability. The poor morphology with numerous defects and the energy level mismatch at the buried interface constrain the open circuit voltage and cause instability. Herein, a sputter-deposited TiOx thin film is used as a buried interface modification layer to address the aforementioned issues. Utilizing in situ grazing-incidence small-angle X-ray scattering (GISAXS) during the sputter deposition, we monitor and unveil the growth process of the TiOx thin film, identifying a 10 nm thickness optimum. The defects at the buried interface are passivated through tuning the growth, leading to a suppressed non-radiative recombination and improved PCE (from 22.19 % to 23.93 %). The evolution of the device performance and the degradation process of PSCs using operando grazing-incidence wide-angle X-ray scattering (GIWAXS) under the protocol ISOS-L-1I explains the enhanced stability introduced by the buried interface modification via a sputter-deposited TiOx thin layer. The perovskite decomposition process and the detrimental formation of PbI2 are both slowed down by the TiOx thin layer.
1170.
J Wolansky, C Hoffmann, M Panhans, L C Winkler, F Talnack, S Hutsch, H Zhang, A Kirch, K M Yallum, H Friedrich, J Kublitski, F Gao, D Spoltore, S C B Mannsfeld, F Ortmann, N Banerji, K Leo, J Benduhn
Sensitive Self-Driven Single-Component Organic Photodetector Based on Vapor-Deposited Small Molecules Journal Article
In: Advanced Materials, vol. 36, no. 50, pp. 2402834, 2024, ISSN: 0935-9648.
@article{nokey,
title = {Sensitive Self-Driven Single-Component Organic Photodetector Based on Vapor-Deposited Small Molecules},
author = {J Wolansky and C Hoffmann and M Panhans and L C Winkler and F Talnack and S Hutsch and H Zhang and A Kirch and K M Yallum and H Friedrich and J Kublitski and F Gao and D Spoltore and S C B Mannsfeld and F Ortmann and N Banerji and K Leo and J Benduhn},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.202402834},
doi = {https://doi.org/10.1002/adma.202402834},
issn = {0935-9648},
year = {2024},
date = {2024-12-12},
journal = {Advanced Materials},
volume = {36},
number = {50},
pages = {2402834},
abstract = {Abstract Typically, organic solar cells (OSCs) and photodetectors (OPDs) comprise an electron donating and accepting material to facilitate efficient charge carrier generation. This approach has proven successful in achieving high-performance devices but has several drawbacks for upscaling and stability. This study presents a fully vacuum-deposited single-component OPD, employing the neat oligothiophene derivative DCV2-5T in the photoactive layer. Free charge carriers are generated with an internal quantum efficiency of 20 % at zero bias. By optimizing the device structure, a very low dark current of 3.4 · 10−11 A cm−2 at −0.1 V is achieved, comparable to the dark current of state-of-the-art bulk heterojunction OPDs. This optimization results in specific detectivities of 1· 1013 Jones (based on noise measurements), accompanied by a fast photoresponse (f-3dB = 200 kHz) and a broad linear dynamic range (\> 150 dB). Ultrafast transient absorption spectroscopy unveils that charge carriers are already formed at very short time scales (\< 1 ps). The surprisingly efficient bulk charge generation mechanism is attributed to a strong electronic coupling of the molecular exciton and charge transfer states. This work demonstrates the very high performance of single-component OPDs and proves that this novel device design is a successful strategy for highly efficient, morphological stable and easily manufacturable devices.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract Typically, organic solar cells (OSCs) and photodetectors (OPDs) comprise an electron donating and accepting material to facilitate efficient charge carrier generation. This approach has proven successful in achieving high-performance devices but has several drawbacks for upscaling and stability. This study presents a fully vacuum-deposited single-component OPD, employing the neat oligothiophene derivative DCV2-5T in the photoactive layer. Free charge carriers are generated with an internal quantum efficiency of 20 % at zero bias. By optimizing the device structure, a very low dark current of 3.4 · 10−11 A cm−2 at −0.1 V is achieved, comparable to the dark current of state-of-the-art bulk heterojunction OPDs. This optimization results in specific detectivities of 1· 1013 Jones (based on noise measurements), accompanied by a fast photoresponse (f-3dB = 200 kHz) and a broad linear dynamic range (> 150 dB). Ultrafast transient absorption spectroscopy unveils that charge carriers are already formed at very short time scales (< 1 ps). The surprisingly efficient bulk charge generation mechanism is attributed to a strong electronic coupling of the molecular exciton and charge transfer states. This work demonstrates the very high performance of single-component OPDs and proves that this novel device design is a successful strategy for highly efficient, morphological stable and easily manufacturable devices.
1169.
J Chen, Q Zhong, E Sirotti, G Zhou, L Wolz, V Streibel, J Dittloff, J Eichhorn, Y Ji, L Zhao, R Zhu, I D Sharp
Ligand-Tuned AgBiS2 Planar Heterojunctions Enable Efficient Ultrathin Solar Cells Journal Article
In: ACS Nano, vol. 18, no. 49, pp. 33348-33358, 2024, ISSN: 1936-0851.
@article{nokey,
title = {Ligand-Tuned AgBiS2 Planar Heterojunctions Enable Efficient Ultrathin Solar Cells},
author = {J Chen and Q Zhong and E Sirotti and G Zhou and L Wolz and V Streibel and J Dittloff and J Eichhorn and Y Ji and L Zhao and R Zhu and I D Sharp},
url = {https://doi.org/10.1021/acsnano.4c07621},
doi = {10.1021/acsnano.4c07621},
issn = {1936-0851},
year = {2024},
date = {2024-12-10},
journal = {ACS Nano},
volume = {18},
number = {49},
pages = {33348-33358},
abstract = {AgBiS2 quantum dots (ABS QDs) have emerged as highly promising candidates for photovoltaic applications due to their strong sunlight absorption, nontoxicity, and elemental availability. Nevertheless, the efficiencies of ABS solar cells currently fall far short of their thermodynamic limits due in large part to sluggish charge transport characteristics in nanocrystal-derived films. In this study, we overcome this limitation by tuning the surfaces of ABS semiconductor QDs via a solvent-induced ligand exchange (SILE) strategy and provide key insights into the role of surface composition on both n- and p-type charge transfer doping, as well as long-range charge transport. Using this approach, the electronic properties of ABS films were systematically modulated, thereby enabling the design of planar p\textendashn heterojunctions featuring favorable band alignment for solar cell applications. Carrier transport and separation are significantly enhanced by the built-in electric fields generated within the ultrathin (30 nm) ABS heterojunction absorber layers, resulting in a notable solar-cell power conversion efficiency of 7.43%. Overall, this study presents a systematic and straightforward strategy to tune not only the surfaces of ABS, but also the electronic properties of solid-state films, thereby enabling junction engineering for the development of advanced semiconductor structures tailored for photovoltaic applications.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
AgBiS2 quantum dots (ABS QDs) have emerged as highly promising candidates for photovoltaic applications due to their strong sunlight absorption, nontoxicity, and elemental availability. Nevertheless, the efficiencies of ABS solar cells currently fall far short of their thermodynamic limits due in large part to sluggish charge transport characteristics in nanocrystal-derived films. In this study, we overcome this limitation by tuning the surfaces of ABS semiconductor QDs via a solvent-induced ligand exchange (SILE) strategy and provide key insights into the role of surface composition on both n- and p-type charge transfer doping, as well as long-range charge transport. Using this approach, the electronic properties of ABS films were systematically modulated, thereby enabling the design of planar p–n heterojunctions featuring favorable band alignment for solar cell applications. Carrier transport and separation are significantly enhanced by the built-in electric fields generated within the ultrathin (30 nm) ABS heterojunction absorber layers, resulting in a notable solar-cell power conversion efficiency of 7.43%. Overall, this study presents a systematic and straightforward strategy to tune not only the surfaces of ABS, but also the electronic properties of solid-state films, thereby enabling junction engineering for the development of advanced semiconductor structures tailored for photovoltaic applications.
1168.
S Tu, T Tian, J Zhang, S Liang, G Pan, X Ma, L Liu, R A Fischer, P Müller-Buschbaum
Electrostatic Tailoring of Freestanding Polymeric Films for Multifunctional Thermoelectrics, Hydrogels, and Actuators Journal Article
In: ACS Nano, 2024, ISSN: 1936-0851.
@article{nokey,
title = {Electrostatic Tailoring of Freestanding Polymeric Films for Multifunctional Thermoelectrics, Hydrogels, and Actuators},
author = {S Tu and T Tian and J Zhang and S Liang and G Pan and X Ma and L Liu and R A Fischer and P M\"{u}ller-Buschbaum},
url = {https://doi.org/10.1021/acsnano.4c12502},
doi = {10.1021/acsnano.4c12502},
issn = {1936-0851},
year = {2024},
date = {2024-12-09},
journal = {ACS Nano},
abstract = {Organic conducting polymer poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) has garnered enormous attention in organic electronics due to its low-cost solution processability, highly tunable conductivity, superior mechanical flexibility, and good biocompatibility together with excellent atmospheric stability. Nevertheless, limited electrical properties and unfavorable water instability of pristine PEDOT:PSS film impede its further implementation in a broad spectrum of practical applications. In this work, the successful tailoring of the intrinsic electrostatic interaction within PEDOT:PSS and consequent optimized electrical properties are enabled by a simple yet effective ionic salt post-treatment strategy. The choice of zinc di[bis(trifluoromethylsulfonyl)imide] (Zn(TFSI)2) not only endows the post-treated PEDOT:PSS film with high electrical properties but also other compelling characteristics, including superior water stability, excellent mechanical flexibility, and fast humidity responsiveness. Multidimensional characterizations are conducted to gain in-depth insights into the mechanisms underlying such improved performance, ranging from intermolecular interactions, polymer conformations, and doping levels to microstructural characteristics. Benefiting from these versatile properties, the as-prepared freestanding Zn(TFSI)2-post-treated PEDOT:PSS films can serve as promising candidates for high-performance polymeric materials integrated into multifunctional flexible electronics, including thermoelectric power generators, conductive hydrogels, and humidity-responsive actuators. This study demonstrates a facile methodology for the exploration of multifunctional conducting polymers, whose implications can extend across a wide range of next-generation wearable devices, bioelectronics, and soft robotics.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Organic conducting polymer poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) has garnered enormous attention in organic electronics due to its low-cost solution processability, highly tunable conductivity, superior mechanical flexibility, and good biocompatibility together with excellent atmospheric stability. Nevertheless, limited electrical properties and unfavorable water instability of pristine PEDOT:PSS film impede its further implementation in a broad spectrum of practical applications. In this work, the successful tailoring of the intrinsic electrostatic interaction within PEDOT:PSS and consequent optimized electrical properties are enabled by a simple yet effective ionic salt post-treatment strategy. The choice of zinc di[bis(trifluoromethylsulfonyl)imide] (Zn(TFSI)2) not only endows the post-treated PEDOT:PSS film with high electrical properties but also other compelling characteristics, including superior water stability, excellent mechanical flexibility, and fast humidity responsiveness. Multidimensional characterizations are conducted to gain in-depth insights into the mechanisms underlying such improved performance, ranging from intermolecular interactions, polymer conformations, and doping levels to microstructural characteristics. Benefiting from these versatile properties, the as-prepared freestanding Zn(TFSI)2-post-treated PEDOT:PSS films can serve as promising candidates for high-performance polymeric materials integrated into multifunctional flexible electronics, including thermoelectric power generators, conductive hydrogels, and humidity-responsive actuators. This study demonstrates a facile methodology for the exploration of multifunctional conducting polymers, whose implications can extend across a wide range of next-generation wearable devices, bioelectronics, and soft robotics.
1167.
N Pettinger, J Schmuck, X Zhou, S Loy, S Zherebtsov, C Kastl, A W Holleitner
Ultrafast mid-infrared interferometric photocurrents in graphene-based two-terminal devices Journal Article
In: Applied Physics Letters, vol. 125, no. 24, 2024, ISSN: 0003-6951.
@article{nokey,
title = {Ultrafast mid-infrared interferometric photocurrents in graphene-based two-terminal devices},
author = {N Pettinger and J Schmuck and X Zhou and S Loy and S Zherebtsov and C Kastl and A W Holleitner},
url = {https://doi.org/10.1063/5.0232394},
doi = {https://doi.org/10.1063/5.0232394},
issn = {0003-6951},
year = {2024},
date = {2024-12-09},
journal = {Applied Physics Letters},
volume = {125},
number = {24},
abstract = {We demonstrate that graphene-based two-terminal devices allow autocorrelating femtosecond mid-infrared pulses with a pulse duration of about 100 fs in the wavelength regime of 5.5\textendash14 μm. The results suggest that the underlying ultrafast detection principle relies on an electric field dominated autocorrelation in combination with the optoelectronic dynamics at the metal\textendashgraphene interfaces. The demonstrated scheme excels because of the ease in nanofabrication of two-terminal graphene-based optoelectronic devices and their robustness.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We demonstrate that graphene-based two-terminal devices allow autocorrelating femtosecond mid-infrared pulses with a pulse duration of about 100 fs in the wavelength regime of 5.5–14 μm. The results suggest that the underlying ultrafast detection principle relies on an electric field dominated autocorrelation in combination with the optoelectronic dynamics at the metal–graphene interfaces. The demonstrated scheme excels because of the ease in nanofabrication of two-terminal graphene-based optoelectronic devices and their robustness.
1166.
D Cahen, Y Rakita, D A Egger, A Kahn
Surface Defects Control Bulk Carrier Densities in Polycrystalline Pb-Halide Perovskites Journal Article
In: Advanced Materials, vol. 36, no. 50, pp. 2407098, 2024, ISSN: 0935-9648.
@article{nokey,
title = {Surface Defects Control Bulk Carrier Densities in Polycrystalline Pb-Halide Perovskites},
author = {D Cahen and Y Rakita and D A Egger and A Kahn},
url = {https://doi.org/10.1002/adma.202407098},
doi = {https://doi.org/10.1002/adma.202407098},
issn = {0935-9648},
year = {2024},
date = {2024-12-01},
journal = {Advanced Materials},
volume = {36},
number = {50},
pages = {2407098},
abstract = {Abstract The (opto)electronic behavior of semiconductors depends on their (quasi-)free electronic carrier densities. These are regulated by semiconductor doping, i.e., controlled ?electronic contamination?. For metal halide perovskites (HaPs), the functional materials in several device types, which already challenge some of the understanding of semiconductor properties, this study shows that doping type, density and properties derived from these, are to a first approximation controlled via their surfaces. This effect, relevant to all semiconductors, and already found for some, is very evident for lead (Pb)-HaPs because of their intrinsically low electrically active bulk and surface defect densities. Volume carrier densities for most polycrystalline Pb-HaP films (\<1 µm grain diameter) are below those resulting from even \< 0.1% of surface sites being electrically active defects. This implies and is consistent with interfacial defects controlling HaP devices in multi-layered structures with most of the action at the two HaP interfaces. Surface and interface passivation effects on bulk electrical properties are relevant to all semiconductors and are crucial for developing those used today. However, because bulk dopant introduction in HaPs at controlled ppm levels for electronic-relevant carrier densities is so difficult, passivation effects are vastly more critical and dominate, to first approximation, their optoelectronic characteristics in devices.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract The (opto)electronic behavior of semiconductors depends on their (quasi-)free electronic carrier densities. These are regulated by semiconductor doping, i.e., controlled ?electronic contamination?. For metal halide perovskites (HaPs), the functional materials in several device types, which already challenge some of the understanding of semiconductor properties, this study shows that doping type, density and properties derived from these, are to a first approximation controlled via their surfaces. This effect, relevant to all semiconductors, and already found for some, is very evident for lead (Pb)-HaPs because of their intrinsically low electrically active bulk and surface defect densities. Volume carrier densities for most polycrystalline Pb-HaP films (<1 µm grain diameter) are below those resulting from even < 0.1% of surface sites being electrically active defects. This implies and is consistent with interfacial defects controlling HaP devices in multi-layered structures with most of the action at the two HaP interfaces. Surface and interface passivation effects on bulk electrical properties are relevant to all semiconductors and are crucial for developing those used today. However, because bulk dopant introduction in HaPs at controlled ppm levels for electronic-relevant carrier densities is so difficult, passivation effects are vastly more critical and dominate, to first approximation, their optoelectronic characteristics in devices.
1165.
X Wang, J Li, R Guo, X Yin, R Luo, D Guo, K Ji, L Dai, H Liang, X Jia, J Chen, Z Jia, Z Shi, S Liu, Y Wang, Q Zhou, T Wang, G Pan, P Müller-Buschbaum, S D Stranks, Y Hou
Regulating phase homogeneity by self-assembled molecules for enhanced efficiency and stability of inverted perovskite solar cells Journal Article
In: Nature Photonics, vol. 18, no. 12, pp. 1269-1275, 2024, ISSN: 1749-4893.
@article{nokey,
title = {Regulating phase homogeneity by self-assembled molecules for enhanced efficiency and stability of inverted perovskite solar cells},
author = {X Wang and J Li and R Guo and X Yin and R Luo and D Guo and K Ji and L Dai and H Liang and X Jia and J Chen and Z Jia and Z Shi and S Liu and Y Wang and Q Zhou and T Wang and G Pan and P M\"{u}ller-Buschbaum and S D Stranks and Y Hou},
url = {https://doi.org/10.1038/s41566-024-01531-x},
doi = {10.1038/s41566-024-01531-x},
issn = {1749-4893},
year = {2024},
date = {2024-12-01},
journal = {Nature Photonics},
volume = {18},
number = {12},
pages = {1269-1275},
abstract = {Heterogeneity in transporting interfaces and perovskites poses a substantial challenge in improving the efficiency of perovskite solar cells from small to large scales, a key barrier to their commercial use. Here we find that the amorphous phases of self-assembling molecules (SAMs) can realize a more homogeneous perovskite growth. Hyperspectral analysis confirms a narrower and blueshifted photoluminescence peak distribution in perovskite/amorphous SAMs. Additionally, fluence-dependent time-resolved photoluminescence reveals a reduced trap-assisted recombination rate of 0.5 × 106 s−1 in amorphous-SAM-based perovskite films. This improvement translates to p\textendashi\textendashn structured perovskite solar cells achieving an efficiency of 25.20% (certified at 24.35%) over a one-square-centimetre area. These cells maintain nearly 100% efficiency after 600 h of 1-sun maximum power point tracking under the ISOS-L-1 protocol, and retain 90% of their initial efficiency after 1,000 h, as evaluated by the ISOS-T-2 protocol.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Heterogeneity in transporting interfaces and perovskites poses a substantial challenge in improving the efficiency of perovskite solar cells from small to large scales, a key barrier to their commercial use. Here we find that the amorphous phases of self-assembling molecules (SAMs) can realize a more homogeneous perovskite growth. Hyperspectral analysis confirms a narrower and blueshifted photoluminescence peak distribution in perovskite/amorphous SAMs. Additionally, fluence-dependent time-resolved photoluminescence reveals a reduced trap-assisted recombination rate of 0.5 × 106 s−1 in amorphous-SAM-based perovskite films. This improvement translates to p–i–n structured perovskite solar cells achieving an efficiency of 25.20% (certified at 24.35%) over a one-square-centimetre area. These cells maintain nearly 100% efficiency after 600 h of 1-sun maximum power point tracking under the ISOS-L-1 protocol, and retain 90% of their initial efficiency after 1,000 h, as evaluated by the ISOS-T-2 protocol.
1164.
K Sun, R Guo, S Liu, D Guo, X Jiang, L F Huber, Y Liang, M A Reus, Z Li, T Guan, J Zhou, M Schwartzkopf, S D Stranks, F Deschler, P Müller-Buschbaum
Deciphering Structure and Charge Carrier Behavior in Reduced-Dimensional Perovskites Journal Article
In: Advanced Functional Materials, vol. 34, no. 52, pp. 2411153, 2024, ISSN: 1616-301X.
@article{nokey,
title = {Deciphering Structure and Charge Carrier Behavior in Reduced-Dimensional Perovskites},
author = {K Sun and R Guo and S Liu and D Guo and X Jiang and L F Huber and Y Liang and M A Reus and Z Li and T Guan and J Zhou and M Schwartzkopf and S D Stranks and F Deschler and P M\"{u}ller-Buschbaum},
url = {https://doi.org/10.1002/adfm.202411153},
doi = {https://doi.org/10.1002/adfm.202411153},
issn = {1616-301X},
year = {2024},
date = {2024-12-01},
journal = {Advanced Functional Materials},
volume = {34},
number = {52},
pages = {2411153},
abstract = {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.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
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.
1163.
Y Li, N Li, S Tu, Y Alon, Z Li, M Betker, D Sun, A Kurmanbay, W Chen, S Liang, S Shi, S V Roth, P Müller-Buschbaum
In: Small, vol. 20, no. 51, pp. 2406279, 2024, ISSN: 1613-6810.
@article{nokey,
title = {Drop-Cast Hybrid Poly(styrene)-b-Poly(ethylene oxide) Metal Salt Films: Solvent Evaporation and Crystallinity-Dependent Evolution of Film Morphology},
author = {Y Li and N Li and S Tu and Y Alon and Z Li and M Betker and D Sun and A Kurmanbay and W Chen and S Liang and S Shi and S V Roth and P M\"{u}ller-Buschbaum},
url = {https://doi.org/10.1002/smll.202406279},
doi = {https://doi.org/10.1002/smll.202406279},
issn = {1613-6810},
year = {2024},
date = {2024-12-01},
journal = {Small},
volume = {20},
number = {51},
pages = {2406279},
abstract = {Abstract Morphology templates of solution?based diblock copolymer (DBC) films with loading metal salts are widely applied in photocatalysts, photovoltaics, and sensors due to their adjustable characteristics based on surface (de?)wetting and microphase separation. The present work investigates the morphologies of drop?cast hybrid films based on poly(styrene)?b?poly(ethylene oxide) (PS?b?PEO) and the metal salts titanium isopropoxide (TTIP) and zinc acetate dehydrate (ZAD) in comparison to the pure DBC. By utilizing scanning electron microscopy, grazing?incidence small? and wide?angle X-ray scattering, and differential scanning calorimetry, we find that the resulting film morphologies depend not only on the presence of metal salts but also on solvent evaporation and crystalline formation. At 20 °C, additional TTIP and ZAD in the polymer template cause the morphology to change from packed globular structures to separated wormlike structures attributed to the changed polymer environment. Furthermore, additional tetrahydrofuran causes irregular structures at the precursor film part and the overlapped wormlike structures to transition into close?packed globular structures at the cap film parts of the pure DBC. In contrast, at 50 °C, the globular structures transit to fingerprint patterns due to the thermal behavior of the crystallizable PEO blocks, and the metal salt additives suppress crystalline structure formation in the PEO domains.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract Morphology templates of solution?based diblock copolymer (DBC) films with loading metal salts are widely applied in photocatalysts, photovoltaics, and sensors due to their adjustable characteristics based on surface (de?)wetting and microphase separation. The present work investigates the morphologies of drop?cast hybrid films based on poly(styrene)?b?poly(ethylene oxide) (PS?b?PEO) and the metal salts titanium isopropoxide (TTIP) and zinc acetate dehydrate (ZAD) in comparison to the pure DBC. By utilizing scanning electron microscopy, grazing?incidence small? and wide?angle X-ray scattering, and differential scanning calorimetry, we find that the resulting film morphologies depend not only on the presence of metal salts but also on solvent evaporation and crystalline formation. At 20 °C, additional TTIP and ZAD in the polymer template cause the morphology to change from packed globular structures to separated wormlike structures attributed to the changed polymer environment. Furthermore, additional tetrahydrofuran causes irregular structures at the precursor film part and the overlapped wormlike structures to transition into close?packed globular structures at the cap film parts of the pure DBC. In contrast, at 50 °C, the globular structures transit to fingerprint patterns due to the thermal behavior of the crystallizable PEO blocks, and the metal salt additives suppress crystalline structure formation in the PEO domains.
1162.
M Cattaneo, K Müller-Caspary, J Barthel, K E Macarthur, N Gauquelin, M Lipinska-Chwalek, J Verbeeck, L J Allen, R E Dunin-Borkowski
Automated detection and mapping of crystal tilt using thermal diffuse scattering in transmission electron microscopy Journal Article
In: Ultramicroscopy, vol. 267, pp. 114050, 2024, ISSN: 0304-3991.
@article{nokey,
title = {Automated detection and mapping of crystal tilt using thermal diffuse scattering in transmission electron microscopy},
author = {M Cattaneo and K M\"{u}ller-Caspary and J Barthel and K E Macarthur and N Gauquelin and M Lipinska-Chwalek and J Verbeeck and L J Allen and R E Dunin-Borkowski},
url = {https://www.sciencedirect.com/science/article/pii/S0304399124001293},
doi = {https://doi.org/10.1016/j.ultramic.2024.114050},
issn = {0304-3991},
year = {2024},
date = {2024-12-01},
journal = {Ultramicroscopy},
volume = {267},
pages = {114050},
abstract = {Quantitative interpretation of transmission electron microscopy (TEM) data of crystalline specimens often requires the accurate knowledge of the local crystal orientation. A method is presented which exploits momentum-resolved scanning TEM (STEM) data to determine the local mistilt from a major zone axis. It is based on a geometric analysis of Kikuchi bands within a single diffraction pattern, yielding the center of the Laue circle. Whereas the approach is not limited to convergent illumination, it is here developed using unit-cell averaged diffraction patterns corresponding to high-resolution STEM settings. In simulation studies, an accuracy of approximately 0.1 mrad is found. The method is implemented in automated software and applied to crystallographic tilt and in-plane rotation mapping in two experimental cases. In particular, orientation maps of high-Mn steel and an epitaxially grown La0.7Sr0.3MnO3-SrTiO3 interface are presented. The results confirm the estimates of the simulation study and indicate that tilt mapping can be performed consistently over a wide field of view with diameters well above 100 nm at unit cell real space sampling.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Quantitative interpretation of transmission electron microscopy (TEM) data of crystalline specimens often requires the accurate knowledge of the local crystal orientation. A method is presented which exploits momentum-resolved scanning TEM (STEM) data to determine the local mistilt from a major zone axis. It is based on a geometric analysis of Kikuchi bands within a single diffraction pattern, yielding the center of the Laue circle. Whereas the approach is not limited to convergent illumination, it is here developed using unit-cell averaged diffraction patterns corresponding to high-resolution STEM settings. In simulation studies, an accuracy of approximately 0.1 mrad is found. The method is implemented in automated software and applied to crystallographic tilt and in-plane rotation mapping in two experimental cases. In particular, orientation maps of high-Mn steel and an epitaxially grown La0.7Sr0.3MnO3-SrTiO3 interface are presented. The results confirm the estimates of the simulation study and indicate that tilt mapping can be performed consistently over a wide field of view with diameters well above 100 nm at unit cell real space sampling.
1161.
D Lei, W Shang, L Cheng, Poonam, W Kaiser, P Banerjee, S Tu, O Henrotte, J Zhang, A Gagliardi, J Jinschek, E Cortés, P Müller-Buschbaum, A S Bandarenka, M Z Hussain, R A Fischer
Ion-Transport Kinetics and Interface Stability Augmentation of Zinc Anodes Based on Fluorinated Covalent Organic Framework Thin Films Journal Article
In: Advanced Energy Materials, vol. 14, no. 46, pp. 2403030, 2024, ISSN: 1614-6832.
@article{nokey,
title = {Ion-Transport Kinetics and Interface Stability Augmentation of Zinc Anodes Based on Fluorinated Covalent Organic Framework Thin Films},
author = {D Lei and W Shang and L Cheng and Poonam and W Kaiser and P Banerjee and S Tu and O Henrotte and J Zhang and A Gagliardi and J Jinschek and E Cort\'{e}s and P M\"{u}ller-Buschbaum and A S Bandarenka and M Z Hussain and R A Fischer},
url = {https://doi.org/10.1002/aenm.202403030},
doi = {https://doi.org/10.1002/aenm.202403030},
issn = {1614-6832},
year = {2024},
date = {2024-12-01},
journal = {Advanced Energy Materials},
volume = {14},
number = {46},
pages = {2403030},
abstract = {Abstract Zinc (Zn) emerges as an ideal anode for aqueous-based energy storage devices because of its safety, non-toxicity, and cost-effectiveness. However, the reversibility of zinc anodes is constrained by unchecked dendrite proliferation and parasitic side reactions. To minimize these adverse effects, a highly oriented, crystalline 2D porous fluorinated covalent organic framework (denoted as TpBD-2F) thin film is in situ synthesized on the Zn anode as a protective layer. The zincophilic and hydrophobic TpBD-2F provides numerous 1D fluorinated nanochannels, which facilitate the hopping/transfer of Zn2+ and repel H2O infiltration, thus regulating Zn2+ flux and inhibiting interfacial corrosion. The resulting TpBD-2F protective film enabled stable plating/stripping in symmetric cells for over 1200 h at 2 mA cm?2. Furthermore, assembled full cells (Zn-ion capacitors) deliver an ultra-long cycling life of over 100 000 cycles at a current density of 5 A g?1, outperforming nearly all reported porous crystalline materials.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract Zinc (Zn) emerges as an ideal anode for aqueous-based energy storage devices because of its safety, non-toxicity, and cost-effectiveness. However, the reversibility of zinc anodes is constrained by unchecked dendrite proliferation and parasitic side reactions. To minimize these adverse effects, a highly oriented, crystalline 2D porous fluorinated covalent organic framework (denoted as TpBD-2F) thin film is in situ synthesized on the Zn anode as a protective layer. The zincophilic and hydrophobic TpBD-2F provides numerous 1D fluorinated nanochannels, which facilitate the hopping/transfer of Zn2+ and repel H2O infiltration, thus regulating Zn2+ flux and inhibiting interfacial corrosion. The resulting TpBD-2F protective film enabled stable plating/stripping in symmetric cells for over 1200 h at 2 mA cm?2. Furthermore, assembled full cells (Zn-ion capacitors) deliver an ultra-long cycling life of over 100 000 cycles at a current density of 5 A g?1, outperforming nearly all reported porous crystalline materials.
1160.
R Götz, R Streng, J Sterzinger, T Steeger, M M Kaye, M Vitort, A S Bandarenka
All-solid-state Li-ion batteries with commercially available electrolytes: A feasibility review Journal Article
In: InfoMat, vol. 6, no. 12, pp. e12627, 2024.
@article{nokey,
title = {All-solid-state Li-ion batteries with commercially available electrolytes: A feasibility review},
author = {R G\"{o}tz and R Streng and J Sterzinger and T Steeger and M M Kaye and M Vitort and A S Bandarenka},
url = {https://doi.org/10.1002/inf2.12627},
doi = {https://doi.org/10.1002/inf2.12627},
year = {2024},
date = {2024-12-01},
journal = {InfoMat},
volume = {6},
number = {12},
pages = {e12627},
abstract = {Abstract The all-solid-state battery (ASSB) concept promises increases in energy density and safety; consequently recent research has focused on optimizing each component of an ideal fully solid battery. However, by doing so, one can also lose oversight of how significantly the individual components impact key parameters. Although this review presents a variety of materials, the included studies limit electrolyte-separator choices to those that are either fully commercial or whose ingredients are readily available; their thicknesses are predefined by the manufacturer or the studies in which they are included. However, we nevertheless discuss both electrode materials. Apart from typical materials, the list of anode materials includes energy-dense candidates, such as lithium metal, or anode-free approaches that are already used in Li-ion batteries. The cathode composition of an ASSB contains a fraction of the solid electrolyte, in addition to the active material and binders/plasticizers, to improve ionic conductivity. Apart from the general screening of reported composites, promising composite cathodes together with constant-thickness separators and metallic lithium anodes are the basis for studying theoretically achievable gravimetric energy densities. The results suggest that procurable oxide electrolytes in the forms of thick pellets (\>300??m) are unable to surpass the performance of already commercially available Li-ion batteries. All-solid-state cells are already capable of exceeding the performance of current batteries with energy densities of 250?Wh?kg?1 by pairing composite cathodes with high mass loadings and using separators that are less than 150??m thick, with even thinner electrolytes (20??m) delivering more than 350?Wh?kg?1.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract The all-solid-state battery (ASSB) concept promises increases in energy density and safety; consequently recent research has focused on optimizing each component of an ideal fully solid battery. However, by doing so, one can also lose oversight of how significantly the individual components impact key parameters. Although this review presents a variety of materials, the included studies limit electrolyte-separator choices to those that are either fully commercial or whose ingredients are readily available; their thicknesses are predefined by the manufacturer or the studies in which they are included. However, we nevertheless discuss both electrode materials. Apart from typical materials, the list of anode materials includes energy-dense candidates, such as lithium metal, or anode-free approaches that are already used in Li-ion batteries. The cathode composition of an ASSB contains a fraction of the solid electrolyte, in addition to the active material and binders/plasticizers, to improve ionic conductivity. Apart from the general screening of reported composites, promising composite cathodes together with constant-thickness separators and metallic lithium anodes are the basis for studying theoretically achievable gravimetric energy densities. The results suggest that procurable oxide electrolytes in the forms of thick pellets (>300??m) are unable to surpass the performance of already commercially available Li-ion batteries. All-solid-state cells are already capable of exceeding the performance of current batteries with energy densities of 250?Wh?kg?1 by pairing composite cathodes with high mass loadings and using separators that are less than 150??m thick, with even thinner electrolytes (20??m) delivering more than 350?Wh?kg?1.
1159.
W Zhang, F Fang, H Zhong, L Huang, H Tang, X Chen, J Hao, L Zhang, L Cao, J Tang, K Zheng, P Müller-Buschbaum, W Chen
Converting Perovskite Nanocrystals to PbS Quantum Dots Toward Short-Wave Infrared Photodetectors Journal Article
In: Advanced Optical Materials, vol. n/a, no. n/a, pp. 2402740, 2024, ISSN: 2195-1071.
@article{nokey,
title = {Converting Perovskite Nanocrystals to PbS Quantum Dots Toward Short-Wave Infrared Photodetectors},
author = {W Zhang and F Fang and H Zhong and L Huang and H Tang and X Chen and J Hao and L Zhang and L Cao and J Tang and K Zheng and P M\"{u}ller-Buschbaum and W Chen},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adom.202402740},
doi = {https://doi.org/10.1002/adom.202402740},
issn = {2195-1071},
year = {2024},
date = {2024-11-29},
journal = {Advanced Optical Materials},
volume = {n/a},
number = {n/a},
pages = {2402740},
abstract = {Abstract PbS quantum dots (QDs) are particularly promising in low-cost short-wave infrared (SWIR) photodetection and imaging applications. Herein, a novel method is introduced defined as the perovskite conversion method (PCM) fabricating PbS QDs by using perovskite nanocrystals (PeNCs) as the lead precursor. The elemental substitution mechanism for PbS QDs from PeNCs is proposed, and it is confirmed that PCM-QDs are exhibiting a smaller trap density due to a natural perovskite passivated surface condition compared to QDs prepared via conventional hot injection method (HIM). Grazing-incidence small-angle X-ray scattering (GISAXS) results indicate that a short-range disorder of the QDs can lead to a long-range disorder configuration in the inner structure of PCM-QD superlattice, which leads to a compact configuration in the QD solid film facilitating charge carrier transport in devices. In a photoconductor-typed SWIR photodetector (PD) comparison, PCM-QD PDs exhibit a high responsivity of 468 A W−1 and detectivities of 2.1 × 1012 Jones, which are almost three times higher than the values in HIM-QDs PDs. Moreover, PCM-QD PDs further show a higher response speed and one magnitude order higher loss frequency than PCM-QD PDs. PCM is promising in the fabrication of high-quality QDs for advanced optoelectronic applications.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract PbS quantum dots (QDs) are particularly promising in low-cost short-wave infrared (SWIR) photodetection and imaging applications. Herein, a novel method is introduced defined as the perovskite conversion method (PCM) fabricating PbS QDs by using perovskite nanocrystals (PeNCs) as the lead precursor. The elemental substitution mechanism for PbS QDs from PeNCs is proposed, and it is confirmed that PCM-QDs are exhibiting a smaller trap density due to a natural perovskite passivated surface condition compared to QDs prepared via conventional hot injection method (HIM). Grazing-incidence small-angle X-ray scattering (GISAXS) results indicate that a short-range disorder of the QDs can lead to a long-range disorder configuration in the inner structure of PCM-QD superlattice, which leads to a compact configuration in the QD solid film facilitating charge carrier transport in devices. In a photoconductor-typed SWIR photodetector (PD) comparison, PCM-QD PDs exhibit a high responsivity of 468 A W−1 and detectivities of 2.1 × 1012 Jones, which are almost three times higher than the values in HIM-QDs PDs. Moreover, PCM-QD PDs further show a higher response speed and one magnitude order higher loss frequency than PCM-QD PDs. PCM is promising in the fabrication of high-quality QDs for advanced optoelectronic applications.