| 219. | M Günther, D Blätte, A L Oechsle, S S Rivas, Yousefi A A Amin, P Müller-Buschbaum, T Bein, T Ameri Increasing Photostability of Inverted Nonfullerene Organic Solar Cells by Using Fullerene Derivative Additives Journal Article ACS Applied Materials & Interfaces, 2021, ISSN: 1944-8244. Abstract | Links | Tags: Foundry Organic, Molecularly Functionalized @article{, title = {Increasing Photostability of Inverted Nonfullerene Organic Solar Cells by Using Fullerene Derivative Additives}, author = {M G\"{u}nther and D Bl\"{a}tte and A L Oechsle and S S Rivas and Yousefi A A Amin and P M\"{u}ller-Buschbaum and T Bein and T Ameri}, url = {https://doi.org/10.1021/acsami.1c00700}, doi = {10.1021/acsami.1c00700}, issn = {1944-8244}, year = {2021}, date = {2021-04-16}, journal = {ACS Applied Materials & Interfaces}, abstract = {Organic solar cells (OSCs) recently achieved efficiencies of over 18% and are well on their way to practical applications, but still considerable stability issues need to be overcome. One major problem emerges from the electron transport material zinc oxide (ZnO), which is mainly used in the inverted device architecture and decomposes many high-performance nonfullerene acceptors due to its photocatalytic activity. In this work, we add three different fullerene derivatives\textemdashPC71BM, ICMA, and BisPCBM\textemdashto an inverted binary PBDB-TF:IT-4F system in order to suppress the photocatalytic degradation of IT-4F on ZnO via the radical scavenging abilities of the fullerenes. We demonstrate that the addition of 5% fullerene not only increases the performance of the binary PBDB-TF:IT-4F system but also significantly improves the device lifetime under UV illumination in an inert atmosphere. While the binary devices lose 20% of their initial efficiency after only 3 h, this time is increased fivefold for the most promising ternary devices with ICMA. We attribute this improvement to a reduced photocatalytic decomposition of IT-4F in the ternary system, which results in a decreased recombination. We propose that the added fullerenes protect the IT-4F by acting as a sacrificial reagent, thereby suppressing the trap state formation. Furthermore, we show that the protective effect of the most promising fullerene ICMA is transferable to two other binary systems PBDB-TF:BTP-4F and PTB7-Th:IT-4F. Importantly, this effect can also increase the air stability of PBDB-TF:IT-4F. This work demonstrates that the addition of fullerene derivatives is a transferable and straightforward strategy to improve the stability of OSCs.}, keywords = {Foundry Organic, Molecularly Functionalized}, pubstate = {published}, tppubtype = {article} } Organic solar cells (OSCs) recently achieved efficiencies of over 18% and are well on their way to practical applications, but still considerable stability issues need to be overcome. One major problem emerges from the electron transport material zinc oxide (ZnO), which is mainly used in the inverted device architecture and decomposes many high-performance nonfullerene acceptors due to its photocatalytic activity. In this work, we add three different fullerene derivatives—PC71BM, ICMA, and BisPCBM—to an inverted binary PBDB-TF:IT-4F system in order to suppress the photocatalytic degradation of IT-4F on ZnO via the radical scavenging abilities of the fullerenes. We demonstrate that the addition of 5% fullerene not only increases the performance of the binary PBDB-TF:IT-4F system but also significantly improves the device lifetime under UV illumination in an inert atmosphere. While the binary devices lose 20% of their initial efficiency after only 3 h, this time is increased fivefold for the most promising ternary devices with ICMA. We attribute this improvement to a reduced photocatalytic decomposition of IT-4F in the ternary system, which results in a decreased recombination. We propose that the added fullerenes protect the IT-4F by acting as a sacrificial reagent, thereby suppressing the trap state formation. Furthermore, we show that the protective effect of the most promising fullerene ICMA is transferable to two other binary systems PBDB-TF:BTP-4F and PTB7-Th:IT-4F. Importantly, this effect can also increase the air stability of PBDB-TF:IT-4F. This work demonstrates that the addition of fullerene derivatives is a transferable and straightforward strategy to improve the stability of OSCs. |
| 218. | S Krause, E Ploetz, J Bohlen, P Schüler, R Yaadav, F Selbach, F Steiner, I Kamińska, P Tinnefeld Graphene-on-Glass Preparation and Cleaning Methods Characterized by Single-Molecule DNA Origami Fluorescent Probes and Raman Spectroscopy Journal Article ACS Nano, 2021, ISSN: 1936-0851. Abstract | Links | Tags: Foundry Organic @article{, title = {Graphene-on-Glass Preparation and Cleaning Methods Characterized by Single-Molecule DNA Origami Fluorescent Probes and Raman Spectroscopy}, author = {S Krause and E Ploetz and J Bohlen and P Sch\"{u}ler and R Yaadav and F Selbach and F Steiner and I Kami\'{n}ska and P Tinnefeld}, url = {https://pubs.acs.org/doi/abs/10.1021/acsnano.0c08383}, doi = {10.1021/acsnano.0c08383}, issn = {1936-0851}, year = {2021}, date = {2021-04-09}, journal = {ACS Nano}, abstract = {Graphene exhibits outstanding fluorescence quenching properties that can become useful for biophysics and biosensing applications, but it remains challenging to harness these advantages due to the complex transfer procedure of chemical vapor deposition-grown graphene to glass coverslips and the low yield of usable samples. Here, we screen 10 graphene-on-glass preparation methods and present an optimized protocol. To obtain the required quality for single-molecule and super-resolution imaging on graphene, we introduce a graphene screening method that avoids consuming the investigated sample. We apply DNA origami nanostructures to place fluorescent probes at a defined distance on top of graphene-on-glass coverslips. Subsequent fluorescence lifetime imaging directly reports on the graphene quality, as deviations from the expected fluorescence lifetime indicate imperfections. We compare the DNA origami probes with conventional techniques for graphene characterization, including light microscopy, atomic force microscopy, and Raman spectroscopy. For the latter, we observe a discrepancy between the graphene quality implied by Raman spectra in comparison to the quality probed by fluorescence lifetime quenching measured at the same position. We attribute this discrepancy to the difference in the effective area that is probed by Raman spectroscopy and fluorescence quenching. Moreover, we demonstrate the applicability of already screened and positively evaluated graphene for studying single-molecule conformational dynamics on a second DNA origami structure. Our results constitute the basis for graphene-based biophysics and super-resolution microscopy.}, keywords = {Foundry Organic}, pubstate = {published}, tppubtype = {article} } Graphene exhibits outstanding fluorescence quenching properties that can become useful for biophysics and biosensing applications, but it remains challenging to harness these advantages due to the complex transfer procedure of chemical vapor deposition-grown graphene to glass coverslips and the low yield of usable samples. Here, we screen 10 graphene-on-glass preparation methods and present an optimized protocol. To obtain the required quality for single-molecule and super-resolution imaging on graphene, we introduce a graphene screening method that avoids consuming the investigated sample. We apply DNA origami nanostructures to place fluorescent probes at a defined distance on top of graphene-on-glass coverslips. Subsequent fluorescence lifetime imaging directly reports on the graphene quality, as deviations from the expected fluorescence lifetime indicate imperfections. We compare the DNA origami probes with conventional techniques for graphene characterization, including light microscopy, atomic force microscopy, and Raman spectroscopy. For the latter, we observe a discrepancy between the graphene quality implied by Raman spectra in comparison to the quality probed by fluorescence lifetime quenching measured at the same position. We attribute this discrepancy to the difference in the effective area that is probed by Raman spectroscopy and fluorescence quenching. Moreover, we demonstrate the applicability of already screened and positively evaluated graphene for studying single-molecule conformational dynamics on a second DNA origami structure. Our results constitute the basis for graphene-based biophysics and super-resolution microscopy. |
| 217. | C Griesser, H Li, E-M Wernig, D Winkler, Shakibi N Nia, T Mairegger, T Götsch, T Schachinger, A Steiger-Thirsfeld, S Penner, D Wielend, D Egger, C Scheurer, K Reuter, J Kunze-Liebhäuser True Nature of the Transition-Metal Carbide/Liquid Interface Determines Its Reactivity Journal Article ACS Catalysis, pp. 4920-4928, 2021. Abstract | Links | Tags: Solid-Liquid @article{, title = {True Nature of the Transition-Metal Carbide/Liquid Interface Determines Its Reactivity}, author = {C Griesser and H Li and E-M Wernig and D Winkler and Shakibi N Nia and T Mairegger and T G\"{o}tsch and T Schachinger and A Steiger-Thirsfeld and S Penner and D Wielend and D Egger and C Scheurer and K Reuter and J Kunze-Liebh\"{a}user}, url = {https://pubs.acs.org/doi/abs/10.1021/acscatal.1c00415}, doi = {10.1021/acscatal.1c00415}, year = {2021}, date = {2021-04-07}, journal = {ACS Catalysis}, pages = {4920-4928}, abstract = {Compound materials, such as transition-metal (TM) carbides, are anticipated to be effective electrocatalysts for the carbon dioxide reduction reaction (CO2RR) to useful chemicals. This expectation is nurtured by density functional theory (DFT) predictions of a break of key adsorption energy scaling relations that limit CO2RR at parent TMs. Here, we evaluate these prospects for hexagonal Mo2C in aqueous electrolytes in a multimethod experiment and theory approach. We find that surface oxide formation completely suppresses the CO2 activation. The oxides are stable down to potentials as low as −1.9 V versus the standard hydrogen electrode, and solely the hydrogen evolution reaction (HER) is found to be active. This generally points to the absolute imperative of recognizing the true interface establishing under operando conditions in computational screening of catalyst materials. When protected from ambient air and used in nonaqueous electrolyte, Mo2C indeed shows CO2RR activity.}, keywords = {Solid-Liquid}, pubstate = {published}, tppubtype = {article} } Compound materials, such as transition-metal (TM) carbides, are anticipated to be effective electrocatalysts for the carbon dioxide reduction reaction (CO2RR) to useful chemicals. This expectation is nurtured by density functional theory (DFT) predictions of a break of key adsorption energy scaling relations that limit CO2RR at parent TMs. Here, we evaluate these prospects for hexagonal Mo2C in aqueous electrolytes in a multimethod experiment and theory approach. We find that surface oxide formation completely suppresses the CO2 activation. The oxides are stable down to potentials as low as −1.9 V versus the standard hydrogen electrode, and solely the hydrogen evolution reaction (HER) is found to be active. This generally points to the absolute imperative of recognizing the true interface establishing under operando conditions in computational screening of catalyst materials. When protected from ambient air and used in nonaqueous electrolyte, Mo2C indeed shows CO2RR activity. |
| 216. | L Sortino, P G Zotev, C L Phillips, A J Brash, J Cambiasso, E Marensi, A M Fox, S A Maier, R Sapienza, A I Tartakovskii Bright single photon emitters with enhanced quantum efficiency in a two-dimensional semiconductor coupled with dielectric nano-antennas Journal Article arXiv preprint arXiv:2103.16986, 2021. Tags: Solid-Solid @article{, title = {Bright single photon emitters with enhanced quantum efficiency in a two-dimensional semiconductor coupled with dielectric nano-antennas}, author = {L Sortino and P G Zotev and C L Phillips and A J Brash and J Cambiasso and E Marensi and A M Fox and S A Maier and R Sapienza and A I Tartakovskii}, year = {2021}, date = {2021-04-05}, journal = {arXiv preprint arXiv:2103.16986}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } |
| 215. | R W Haid, R M Kluge, T O Schmidt, A S Bandarenka In-situ Detection of Active Sites for Carbon-Based Bifunctional Oxygen Reduction and Evolution Catalysis Journal Article Electrochimica Acta, pp. 138285, 2021, ISSN: 0013-4686. Abstract | Links | Tags: Foundry Inorganic, Solid-Solid @article{, title = {In-situ Detection of Active Sites for Carbon-Based Bifunctional Oxygen Reduction and Evolution Catalysis}, author = {R W Haid and R M Kluge and T O Schmidt and A S Bandarenka}, url = {https://www.sciencedirect.com/science/article/pii/S0013468621005752}, doi = {https://doi.org/10.1016/j.electacta.2021.138285}, issn = {0013-4686}, year = {2021}, date = {2021-04-02}, journal = {Electrochimica Acta}, pages = {138285}, abstract = {Due to their availability and electrochemical versatility, carbon-based electrodes are becoming an increasingly popular option as electrocatalysts for fuel cells and metal-air batteries. Additionally, they show great potential as bifunctional catalysts for the oxygen reduction and evolution reaction (ORR/OER) in an alkaline medium. However, to compete with state-of-the-art catalysts, the nature of the active sites and the surface stability under reaction conditions need to be understood in depth. Here, we present a principle study on highly oriented pyrolytic graphite (HOPG), evaluating the surface behavior under both ORR and OER conditions in 0.1 M KOH. We use noise analysis in electrochemical scanning tunneling microscopy (n-EC-STM) to monitor and compare ORR and OER active sites with resolution down to the nanoscale. Furthermore, surface degradation can be evaluated during the operation. We find that close to the respective reaction onset, step sites and defects are active for both ORR and OER. Terraces sites are largely inactive and only become involved in the OER at higher potentials. This could imply corrosion of the carbon. However, since the observed surface structures remain unaltered before and after applying the OER in our experiments, we find no clear evidence of surface destruction. These fundamental insights could inspire further research concerning the active sites and stability of carbon-based catalysts as well as carbon support structures, to discover ways to tune the surface activity and stability to the dedicated purpose.}, keywords = {Foundry Inorganic, Solid-Solid}, pubstate = {published}, tppubtype = {article} } Due to their availability and electrochemical versatility, carbon-based electrodes are becoming an increasingly popular option as electrocatalysts for fuel cells and metal-air batteries. Additionally, they show great potential as bifunctional catalysts for the oxygen reduction and evolution reaction (ORR/OER) in an alkaline medium. However, to compete with state-of-the-art catalysts, the nature of the active sites and the surface stability under reaction conditions need to be understood in depth. Here, we present a principle study on highly oriented pyrolytic graphite (HOPG), evaluating the surface behavior under both ORR and OER conditions in 0.1 M KOH. We use noise analysis in electrochemical scanning tunneling microscopy (n-EC-STM) to monitor and compare ORR and OER active sites with resolution down to the nanoscale. Furthermore, surface degradation can be evaluated during the operation. We find that close to the respective reaction onset, step sites and defects are active for both ORR and OER. Terraces sites are largely inactive and only become involved in the OER at higher potentials. This could imply corrosion of the carbon. However, since the observed surface structures remain unaltered before and after applying the OER in our experiments, we find no clear evidence of surface destruction. These fundamental insights could inspire further research concerning the active sites and stability of carbon-based catalysts as well as carbon support structures, to discover ways to tune the surface activity and stability to the dedicated purpose. |
| 214. | H Li, K Liu, J Fu, K Chen, K Yang, Y Lin, B Yang, Q Wang, H Pan, Z Cai, H Li, M Cao, J Hu, Y-R Lu, T-S Chan, E Cortés, A Fratalocchi, M Liu Paired Ru‒O‒Mo ensemble for efficient and stable alkaline hydrogen evolution reaction Journal Article Nano Energy, 82 , pp. 105767, 2021, ISSN: 2211-2855. Abstract | Links | Tags: Solid-Liquid @article{, title = {Paired Ru‒O‒Mo ensemble for efficient and stable alkaline hydrogen evolution reaction}, author = {H Li and K Liu and J Fu and K Chen and K Yang and Y Lin and B Yang and Q Wang and H Pan and Z Cai and H Li and M Cao and J Hu and Y-R Lu and T-S Chan and E Cort\'{e}s and A Fratalocchi and M Liu}, url = {http://www.sciencedirect.com/science/article/pii/S2211285521000252}, doi = {https://doi.org/10.1016/j.nanoen.2021.105767}, issn = {2211-2855}, year = {2021}, date = {2021-04-01}, journal = {Nano Energy}, volume = {82}, pages = {105767}, abstract = {Electrocatalytic hydrogen evolution reaction (HER) in alkaline media is a promising electrochemical energy conversion strategy. Ruthenium (Ru) is an efficient catalyst with a desirable cost for HER, however, the sluggish H2O dissociation process, due to the low H2O adsorption on its surface, currently hampers the performances of this catalyst in alkaline HER. Herein, we demonstrate that the H2O adsorption improves significantly by the construction of Ru\textendashO\textendashMo sites. We prepared Ru/MoO2 catalysts with Ru\textendashO\textendashMo sites through a facile thermal treatment process and assessed the creation of Ru\textendashO\textendashMo interfaces by transmission electron microscope (TEM) and extended X-ray absorption fine structure (EXAFS). By using Fourier-transform infrared spectroscopy (FTIR) and H2O adsorption tests, we proved Ru\textendashO\textendashMo sites have tenfold stronger H2O adsorption ability than that of Ru catalyst. The catalysts with Ru\textendashO\textendashMo sites exhibited a state-of-the-art overpotential of 16 mV at 10 mA cm\textendash2 in 1 M KOH electrolyte, demonstrating a threefold reduction than the previous bests of Ru (59 mV) and commercial Pt (31 mV) catalysts. We proved the stability of these performances over 40 h without decline. These results could open a new path for designing efficient and stable catalysts.}, keywords = {Solid-Liquid}, pubstate = {published}, tppubtype = {article} } Electrocatalytic hydrogen evolution reaction (HER) in alkaline media is a promising electrochemical energy conversion strategy. Ruthenium (Ru) is an efficient catalyst with a desirable cost for HER, however, the sluggish H2O dissociation process, due to the low H2O adsorption on its surface, currently hampers the performances of this catalyst in alkaline HER. Herein, we demonstrate that the H2O adsorption improves significantly by the construction of Ru–O–Mo sites. We prepared Ru/MoO2 catalysts with Ru–O–Mo sites through a facile thermal treatment process and assessed the creation of Ru–O–Mo interfaces by transmission electron microscope (TEM) and extended X-ray absorption fine structure (EXAFS). By using Fourier-transform infrared spectroscopy (FTIR) and H2O adsorption tests, we proved Ru–O–Mo sites have tenfold stronger H2O adsorption ability than that of Ru catalyst. The catalysts with Ru–O–Mo sites exhibited a state-of-the-art overpotential of 16 mV at 10 mA cm–2 in 1 M KOH electrolyte, demonstrating a threefold reduction than the previous bests of Ru (59 mV) and commercial Pt (31 mV) catalysts. We proved the stability of these performances over 40 h without decline. These results could open a new path for designing efficient and stable catalysts. |
| 213. | S Kaiser, F Maleki, K Zhang, W Harbich, U Heiz, S Tosoni, B A Lechner, G Pacchioni, F Esch Cluster Catalysis with Lattice Oxygen: Tracing Oxygen Transport from a Magnetite (001) Support onto Small Pt Clusters Journal Article arXiv preprint arXiv:2103.16413, 2021. Tags: Solid-Solid @article{, title = {Cluster Catalysis with Lattice Oxygen: Tracing Oxygen Transport from a Magnetite (001) Support onto Small Pt Clusters}, author = {S Kaiser and F Maleki and K Zhang and W Harbich and U Heiz and S Tosoni and B A Lechner and G Pacchioni and F Esch}, year = {2021}, date = {2021-03-30}, journal = {arXiv preprint arXiv:2103.16413}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } |
| 212. | A Mähringer, M Döblinger, M Hennemann, C Gruber, D Fehn, P I Scheurle, P Hosseini, I Santourian, A Schirmacher, J M Rotter, G Wittstock, K Meyer, T Clark, T Bein, D D Medina An electrically conducting three-dimensional iron-catecholate porous framework Journal Article Angewandte Chemie International Edition, n/a (n/a), 2021, ISSN: 1433-7851. Abstract | Links | Tags: Foundry Inorganic @article{, title = {An electrically conducting three-dimensional iron-catecholate porous framework}, author = {A M\"{a}hringer and M D\"{o}blinger and M Hennemann and C Gruber and D Fehn and P I Scheurle and P Hosseini and I Santourian and A Schirmacher and J M Rotter and G Wittstock and K Meyer and T Clark and T Bein and D D Medina}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202102670}, doi = {https://doi.org/10.1002/anie.202102670}, issn = {1433-7851}, year = {2021}, date = {2021-03-29}, journal = {Angewandte Chemie International Edition}, volume = {n/a}, number = {n/a}, abstract = {Here, we report the synthesis of a unique cubic metal-organic framework (MOF), the Fe-HHTP-MOF, comprising hexahydroxytriphenylene (HHTP) supertetrahedral units and FeIII ions, arranged in a diamond topology. The MOF is synthesized under solvothermal conditions, yielding a highly crystalline, deep black powder, with crystallites of 300-500 nm size and tetrahedral morphology. Nitrogen sorption analysis indicates a highly porous material with a surface area exceeding 1400 m2 g−1. Furthermore, Fe-HHTP-MOF shows broadband absorption from 475 nm up to 1900 nm with excellent absorption capability of 98.5% of the incoming light over the visible spectral region. Electrical conductivity measurements of pressed pellets reveal a high intrinsic electrical conductivity of up to 10−3 S cm−1. Quantum mechanical calculations predict Fe-HHTP-MOF to be an efficient electron conductor, exhibiting continuous charge-carrier pathways throughout the structure. This report expands the paradigm of intrinsically electroactive MOFs, serving as a solid basis for the development of highly porous, ordered frameworks with enhanced electrical conductivity.}, keywords = {Foundry Inorganic}, pubstate = {published}, tppubtype = {article} } Here, we report the synthesis of a unique cubic metal-organic framework (MOF), the Fe-HHTP-MOF, comprising hexahydroxytriphenylene (HHTP) supertetrahedral units and FeIII ions, arranged in a diamond topology. The MOF is synthesized under solvothermal conditions, yielding a highly crystalline, deep black powder, with crystallites of 300-500 nm size and tetrahedral morphology. Nitrogen sorption analysis indicates a highly porous material with a surface area exceeding 1400 m2 g−1. Furthermore, Fe-HHTP-MOF shows broadband absorption from 475 nm up to 1900 nm with excellent absorption capability of 98.5% of the incoming light over the visible spectral region. Electrical conductivity measurements of pressed pellets reveal a high intrinsic electrical conductivity of up to 10−3 S cm−1. Quantum mechanical calculations predict Fe-HHTP-MOF to be an efficient electron conductor, exhibiting continuous charge-carrier pathways throughout the structure. This report expands the paradigm of intrinsically electroactive MOFs, serving as a solid basis for the development of highly porous, ordered frameworks with enhanced electrical conductivity. |
| 211. | F Devaux, X Li, D Sluysmans, V Maurizot, E Bakalis, F Zerbetto, I Huc, A-S Duwez Single-molecule mechanics of synthetic aromatic amide helices: Ultrafast and robust non-dissipative winding Journal Article Chem, 2021, ISSN: 2451-9294. Tags: Foundry Organic @article{, title = {Single-molecule mechanics of synthetic aromatic amide helices: Ultrafast and robust non-dissipative winding}, author = {F Devaux and X Li and D Sluysmans and V Maurizot and E Bakalis and F Zerbetto and I Huc and A-S Duwez}, issn = {2451-9294}, year = {2021}, date = {2021-03-26}, journal = {Chem}, keywords = {Foundry Organic}, pubstate = {published}, tppubtype = {article} } |
| 210. | R Kluge, R W Haid, I Stephens, F Calle-Vallejo, A Bandarenka Monitoring Active Sites for Hydrogen Evolution Reaction at Model Carbon Surfaces Journal Article Physical Chemistry Chemical Physics, 2021, ISSN: 1463-9076. Abstract | Links | Tags: Foundry Inorganic, Solid-Solid @article{, title = {Monitoring Active Sites for Hydrogen Evolution Reaction at Model Carbon Surfaces}, author = {R Kluge and R W Haid and I Stephens and F Calle-Vallejo and A Bandarenka}, url = {http://dx.doi.org/10.1039/D1CP00434D}, doi = {10.1039/D1CP00434D}, issn = {1463-9076}, year = {2021}, date = {2021-03-25}, journal = {Physical Chemistry Chemical Physics}, abstract = {Carbon is ubiquitous as an electrode material in electrochemical energy conversion devices. If used as support material, the evolution of H2 is undesired on carbon. However, recently carbon-based materials are of high interest as economic and eco-conscious alternative to noble metal catalysts. The targeted design of improved carbon electrode materials requires atomic scale insight into the structure of the sites that catalyse H2 evolution. This work demonstrates that electrochemical scanning tunnelling microscopy under reaction conditions (n-EC-STM) can monitor active sites of highly oriented pyrolytic graphite for the hydrogen evolution reaction. With down to atomic resolution, the most active sites in acidic medium are pinpointed near edge sites and defects, whereas the basal planes remain inactive. Density functional theory calculations support these findings and reveal that only specific defects on graphite are active. Motivated by these results, the extensive usage of n-EC-STM on doped carbon-based materials is encouraged to locate their active sites and guide the synthesis of enhanced electrocatalysts.}, keywords = {Foundry Inorganic, Solid-Solid}, pubstate = {published}, tppubtype = {article} } Carbon is ubiquitous as an electrode material in electrochemical energy conversion devices. If used as support material, the evolution of H2 is undesired on carbon. However, recently carbon-based materials are of high interest as economic and eco-conscious alternative to noble metal catalysts. The targeted design of improved carbon electrode materials requires atomic scale insight into the structure of the sites that catalyse H2 evolution. This work demonstrates that electrochemical scanning tunnelling microscopy under reaction conditions (n-EC-STM) can monitor active sites of highly oriented pyrolytic graphite for the hydrogen evolution reaction. With down to atomic resolution, the most active sites in acidic medium are pinpointed near edge sites and defects, whereas the basal planes remain inactive. Density functional theory calculations support these findings and reveal that only specific defects on graphite are active. Motivated by these results, the extensive usage of n-EC-STM on doped carbon-based materials is encouraged to locate their active sites and guide the synthesis of enhanced electrocatalysts. |
| 209. | D Bessinger, K Muggli, M Beetz, F Auras, T Bein Fast-Switching Vis–IR Electrochromic Covalent Organic Frameworks Journal Article Journal of the American Chemical Society, 2021, ISSN: 0002-7863. Abstract | Links | Tags: Foundry Organic, Molecularly-Functionalized @article{, title = {Fast-Switching Vis\textendashIR Electrochromic Covalent Organic Frameworks}, author = {D Bessinger and K Muggli and M Beetz and F Auras and T Bein}, url = {https://doi.org/10.1021/jacs.0c12392}, doi = {10.1021/jacs.0c12392}, issn = {0002-7863}, year = {2021}, date = {2021-03-16}, journal = {Journal of the American Chemical Society}, abstract = {Electrochromic coatings are promising for applications in smart windows or energy-efficient optical displays. However, classical inorganic electrochromic materials such as WO3 suffer from low coloration efficiency and slow switching speed. We have developed highly efficient and fast-switching electrochromic thin films based on fully organic, porous covalent organic frameworks (COFs). The low band gap COFs have strong vis\textendashNIR absorption bands in the neutral state, which shift significantly upon electrochemical oxidation. Fully reversible absorption changes by close to 3 OD can be triggered at low operating voltages and low charge per unit area. Our champion material reaches an electrochromic coloration efficiency of 858 cm2 C\textendash1 at 880 nm and retains >95% of its electrochromic response over 100 oxidation/reduction cycles. Furthermore, the electrochromic switching is extremely fast with response times below 0.4 s for the oxidation and around 0.2 s for the reduction, outperforming previous COFs by at least an order of magnitude and rendering these materials some of the fastest-switching frameworks to date. This combination of high coloration efficiency and very fast switching reveals intriguing opportunities for applications of porous organic electrochromic materials.}, keywords = {Foundry Organic, Molecularly-Functionalized}, pubstate = {published}, tppubtype = {article} } Electrochromic coatings are promising for applications in smart windows or energy-efficient optical displays. However, classical inorganic electrochromic materials such as WO3 suffer from low coloration efficiency and slow switching speed. We have developed highly efficient and fast-switching electrochromic thin films based on fully organic, porous covalent organic frameworks (COFs). The low band gap COFs have strong vis–NIR absorption bands in the neutral state, which shift significantly upon electrochemical oxidation. Fully reversible absorption changes by close to 3 OD can be triggered at low operating voltages and low charge per unit area. Our champion material reaches an electrochromic coloration efficiency of 858 cm2 C–1 at 880 nm and retains >95% of its electrochromic response over 100 oxidation/reduction cycles. Furthermore, the electrochromic switching is extremely fast with response times below 0.4 s for the oxidation and around 0.2 s for the reduction, outperforming previous COFs by at least an order of magnitude and rendering these materials some of the fastest-switching frameworks to date. This combination of high coloration efficiency and very fast switching reveals intriguing opportunities for applications of porous organic electrochromic materials. |
| 208. | J P Sabawa, A S Bandarenka Investigation of degradation mechanisms in PEM fuel cells caused by low-temperature cycles Journal Article International Journal of Hydrogen Energy, 2021, ISSN: 0360-3199. Abstract | Links | Tags: Foundry Inorganic @article{, title = {Investigation of degradation mechanisms in PEM fuel cells caused by low-temperature cycles}, author = {J P Sabawa and A S Bandarenka}, url = {https://www.sciencedirect.com/science/article/pii/S0360319921005917}, doi = {https://doi.org/10.1016/j.ijhydene.2021.02.088}, issn = {0360-3199}, year = {2021}, date = {2021-03-05}, journal = {International Journal of Hydrogen Energy}, abstract = {Environmental influences, especially temperatures below the freezing point, can affect the performance and long-term stability of PEMFCs. Within the scope of this research, a completely new test procedure was developed to characterize PEMFC single cells with respect to their long-term stability at temperature cycles between 80 °C and −10 °C. Using this procedure, the behavior of PEMFC single cells (active surface area of 43.6 cm2) with different cathode-ionomer-to-carbon (I/C) weight ratios (0.5/1.0/1.5) was evaluated. The generated in-situ measurement data clearly demonstrate that the performance of each PEMFC single cell changes individually as a function of the cathode I/C-ratio during the 120 stress cycles. While the MEA with an I/C ratio of 0.5 showed a power loss of ~1.49%, the MEAs with an I/C ratio of 1.0 and 1.5 showed a power loss of about ~7.75% and ~24.7%, respectively. The subsequent post-mortem ex-situ analyses clearly showed how the test procedure and the different I/C-ratios affected the changes in the catalyst layers (CL). The destructive mechanisms responsible for the changes can be divided into two categories: One part was driven by rapid enthalpy change leading to mechanical failure, and the other part, which led to the reduction of cathode CL thickness, was driven by rapid potential changes and potential shifts (overpotentials). This reduction in cathode CL thickness ultimately leads to an accumulation and excessive load of ionomer in the direction of GDL, resulting in a reduction in pore size, a shift in the core reaction area, and high O2 transport resistance.}, keywords = {Foundry Inorganic}, pubstate = {published}, tppubtype = {article} } Environmental influences, especially temperatures below the freezing point, can affect the performance and long-term stability of PEMFCs. Within the scope of this research, a completely new test procedure was developed to characterize PEMFC single cells with respect to their long-term stability at temperature cycles between 80 °C and −10 °C. Using this procedure, the behavior of PEMFC single cells (active surface area of 43.6 cm2) with different cathode-ionomer-to-carbon (I/C) weight ratios (0.5/1.0/1.5) was evaluated. The generated in-situ measurement data clearly demonstrate that the performance of each PEMFC single cell changes individually as a function of the cathode I/C-ratio during the 120 stress cycles. While the MEA with an I/C ratio of 0.5 showed a power loss of ~1.49%, the MEAs with an I/C ratio of 1.0 and 1.5 showed a power loss of about ~7.75% and ~24.7%, respectively. The subsequent post-mortem ex-situ analyses clearly showed how the test procedure and the different I/C-ratios affected the changes in the catalyst layers (CL). The destructive mechanisms responsible for the changes can be divided into two categories: One part was driven by rapid enthalpy change leading to mechanical failure, and the other part, which led to the reduction of cathode CL thickness, was driven by rapid potential changes and potential shifts (overpotentials). This reduction in cathode CL thickness ultimately leads to an accumulation and excessive load of ionomer in the direction of GDL, resulting in a reduction in pore size, a shift in the core reaction area, and high O2 transport resistance. |
| 207. | K Hübner, H Joshi, A Aksimentiev, F D Stefani, P Tinnefeld, G P Acuna Determining the In-Plane Orientation and Binding Mode of Single Fluorescent Dyes in DNA Origami Structures Journal Article ACS Nano, 2021, ISSN: 1936-0851. Abstract | Links | Tags: Foundry Organic @article{, title = {Determining the In-Plane Orientation and Binding Mode of Single Fluorescent Dyes in DNA Origami Structures}, author = {K H\"{u}bner and H Joshi and A Aksimentiev and F D Stefani and P Tinnefeld and G P Acuna}, url = {https://doi.org/10.1021/acsnano.0c10259}, doi = {10.1021/acsnano.0c10259}, issn = {1936-0851}, year = {2021}, date = {2021-03-04}, journal = {ACS Nano}, abstract = {We present a technique to determine the orientation of single fluorophores attached to DNA origami structures based on two measurements. First, the orientation of the absorption transition dipole of the molecule is determined through a polarization-resolved excitation measurement. Second, the orientation of the DNA origami structure is obtained from a DNA-PAINT nanoscopy measurement. Both measurements are performed consecutively on a fluorescence wide-field microscope. We employed this approach to study the orientation of single ATTO 647N, ATTO 643, and Cy5 fluorophores covalently attached to a 2D rectangular DNA origami structure with different nanoenvironments, achieved by changing both the fluorophores’ binding position and immediate vicinity. Our results show that when fluorophores are incorporated with additional space, for example, by omitting nucleotides in an elsewise double-stranded environment, they tend to stick to the DNA and to adopt a preferred orientation that depends more on the specific molecular environment than on the fluorophore type. With the aid of all-atom molecular dynamics simulations, we rationalized our observations and provide insight into the fluorophores’ probable binding modes. We believe this work constitutes an important step toward manipulating the orientation of single fluorophores in DNA origami structures, which is vital for the development of more efficient and reproducible self-assembled nanophotonic devices.}, keywords = {Foundry Organic}, pubstate = {published}, tppubtype = {article} } We present a technique to determine the orientation of single fluorophores attached to DNA origami structures based on two measurements. First, the orientation of the absorption transition dipole of the molecule is determined through a polarization-resolved excitation measurement. Second, the orientation of the DNA origami structure is obtained from a DNA-PAINT nanoscopy measurement. Both measurements are performed consecutively on a fluorescence wide-field microscope. We employed this approach to study the orientation of single ATTO 647N, ATTO 643, and Cy5 fluorophores covalently attached to a 2D rectangular DNA origami structure with different nanoenvironments, achieved by changing both the fluorophores’ binding position and immediate vicinity. Our results show that when fluorophores are incorporated with additional space, for example, by omitting nucleotides in an elsewise double-stranded environment, they tend to stick to the DNA and to adopt a preferred orientation that depends more on the specific molecular environment than on the fluorophore type. With the aid of all-atom molecular dynamics simulations, we rationalized our observations and provide insight into the fluorophores’ probable binding modes. We believe this work constitutes an important step toward manipulating the orientation of single fluorophores in DNA origami structures, which is vital for the development of more efficient and reproducible self-assembled nanophotonic devices. |
| 206. | A Auer, X Ding, A S Bandarenka, J Kunze-Liebhäuser The Potential of Zero Charge and the Electrochemical Interface Structure of Cu(111) in Alkaline Solutions Journal Article The Journal of Physical Chemistry C, 2021, ISSN: 1932-7447. Abstract | Links | Tags: Foundry Inorganic, Solid-Liquid @article{, title = {The Potential of Zero Charge and the Electrochemical Interface Structure of Cu(111) in Alkaline Solutions}, author = {A Auer and X Ding and A S Bandarenka and J Kunze-Liebh\"{a}user}, url = {https://doi.org/10.1021/acs.jpcc.0c09289}, doi = {10.1021/acs.jpcc.0c09289}, issn = {1932-7447}, year = {2021}, date = {2021-03-01}, journal = {The Journal of Physical Chemistry C}, abstract = {Copper (Cu) is a unique electrocatalyst, which is able to efficiently oxidize CO at very low overpotentials and reduce CO2 to valuable fuels with reasonable Faradaic efficiencies. Yet, knowledge of its electrochemical properties at the solid/liquid interface is still scarce. Here, we present the first two-stranded correlation of the potential of zero free charge (pzfc) of Cu(111) in alkaline electrolyte at different pH values through application of nanosecond laser pulses and the corresponding interfacial structure changes by in situ electrochemical scanning tunneling microscopy imaging. The pzfc of Cu(111) at pH 13 is identified at −0.73 VSHE in the apparent double layer region, prior to the onset of hydroxide adsorption. It shifts by (88 ± 4) mV to more positive potentials per decreasing pH unit. At the pzfc, Cu(111) shows structural dynamics at both pH 13 and pH 11, which can be understood as the onset of surface restructuring. At higher potentials, full reconstruction and electric field dependent OH adsorption occurs, which causes a remarkable decrease in the atomic density of the first Cu layer. The expansion of the Cu\textendashCu distance to 0.3 nm generates a hexagonal Moir\'{e} pattern, on which the adsorbed OH forms a commensurate (1 × 2) adlayer structure with a steady state coverage of 0.5 monolayers at pH 13. Our experimental findings shed light on the true charge distribution and its interrelation with the atomic structure of the electrochemical interface of Cu.}, keywords = {Foundry Inorganic, Solid-Liquid}, pubstate = {published}, tppubtype = {article} } Copper (Cu) is a unique electrocatalyst, which is able to efficiently oxidize CO at very low overpotentials and reduce CO2 to valuable fuels with reasonable Faradaic efficiencies. Yet, knowledge of its electrochemical properties at the solid/liquid interface is still scarce. Here, we present the first two-stranded correlation of the potential of zero free charge (pzfc) of Cu(111) in alkaline electrolyte at different pH values through application of nanosecond laser pulses and the corresponding interfacial structure changes by in situ electrochemical scanning tunneling microscopy imaging. The pzfc of Cu(111) at pH 13 is identified at −0.73 VSHE in the apparent double layer region, prior to the onset of hydroxide adsorption. It shifts by (88 ± 4) mV to more positive potentials per decreasing pH unit. At the pzfc, Cu(111) shows structural dynamics at both pH 13 and pH 11, which can be understood as the onset of surface restructuring. At higher potentials, full reconstruction and electric field dependent OH adsorption occurs, which causes a remarkable decrease in the atomic density of the first Cu layer. The expansion of the Cu–Cu distance to 0.3 nm generates a hexagonal Moiré pattern, on which the adsorbed OH forms a commensurate (1 × 2) adlayer structure with a steady state coverage of 0.5 monolayers at pH 13. Our experimental findings shed light on the true charge distribution and its interrelation with the atomic structure of the electrochemical interface of Cu. |
| 205. | G J Hedley, T Schröder, F Steiner, T Eder, F J Hofmann, S Bange, D Laux, S Höger, P Tinnefeld, J M Lupton, J Vogelsang Picosecond time-resolved photon antibunching measures nanoscale exciton motion and the true number of chromophores Journal Article Nature Communications, 12 (1), pp. 1327, 2021, ISSN: 2041-1723. Abstract | Links | Tags: Foundry Organic, Molecularly-Functionalized @article{, title = {Picosecond time-resolved photon antibunching measures nanoscale exciton motion and the true number of chromophores}, author = {G J Hedley and T Schr\"{o}der and F Steiner and T Eder and F J Hofmann and S Bange and D Laux and S H\"{o}ger and P Tinnefeld and J M Lupton and J Vogelsang}, url = {https://doi.org/10.1038/s41467-021-21474-z}, doi = {10.1038/s41467-021-21474-z}, issn = {2041-1723}, year = {2021}, date = {2021-02-26}, journal = {Nature Communications}, volume = {12}, number = {1}, pages = {1327}, abstract = {The particle-like nature of light becomes evident in the photon statistics of fluorescence from single quantum systems as photon antibunching. In multichromophoric systems, exciton diffusion and subsequent annihilation occurs. These processes also yield photon antibunching but cannot be interpreted reliably. Here we develop picosecond time-resolved antibunching to identify and decode such processes. We use this method to measure the true number of chromophores on well-defined multichromophoric DNA-origami structures, and precisely determine the distance-dependent rates of annihilation between excitons. Further, this allows us to measure exciton diffusion in mesoscopic H- and J-type conjugated-polymer aggregates. We distinguish between one-dimensional intra-chain and three-dimensional inter-chain exciton diffusion at different times after excitation and determine the disorder-dependent diffusion lengths. Our method provides a powerful lens through which excitons can be studied at the single-particle level, enabling the rational design of improved excitonic probes such as ultra-bright fluorescent nanoparticles and materials for optoelectronic devices.}, keywords = {Foundry Organic, Molecularly-Functionalized}, pubstate = {published}, tppubtype = {article} } The particle-like nature of light becomes evident in the photon statistics of fluorescence from single quantum systems as photon antibunching. In multichromophoric systems, exciton diffusion and subsequent annihilation occurs. These processes also yield photon antibunching but cannot be interpreted reliably. Here we develop picosecond time-resolved antibunching to identify and decode such processes. We use this method to measure the true number of chromophores on well-defined multichromophoric DNA-origami structures, and precisely determine the distance-dependent rates of annihilation between excitons. Further, this allows us to measure exciton diffusion in mesoscopic H- and J-type conjugated-polymer aggregates. We distinguish between one-dimensional intra-chain and three-dimensional inter-chain exciton diffusion at different times after excitation and determine the disorder-dependent diffusion lengths. Our method provides a powerful lens through which excitons can be studied at the single-particle level, enabling the rational design of improved excitonic probes such as ultra-bright fluorescent nanoparticles and materials for optoelectronic devices. |
| 204. | A M Molszalai, B Siarry, J Lukin, S Giusti, N Unsain, A Cáceres, F Steiner, P Tinnefeld, D Refojo, T M Jovin, F D Stefani Super-resolution Imaging of Energy Transfer by Intensity-Based STED-FRET Journal Article Nano Letters, 2021, ISSN: 1530-6984. Abstract | Links | Tags: Foundry Organic, Molecularly-Functionalized @article{, title = {Super-resolution Imaging of Energy Transfer by Intensity-Based STED-FRET}, author = {A M Molszalai and B Siarry and J Lukin and S Giusti and N Unsain and A C\'{a}ceres and F Steiner and P Tinnefeld and D Refojo and T M Jovin and F D Stefani}, url = {https://doi.org/10.1021/acs.nanolett.1c00158}, doi = {10.1021/acs.nanolett.1c00158}, issn = {1530-6984}, year = {2021}, date = {2021-02-23}, journal = {Nano Letters}, abstract = {F\"{o}rster resonance energy transfer (FRET) imaging methods provide unique insight into the spatial distribution of energy transfer and (bio)molecular interaction events, though they deliver average information for an ensemble of events included in a diffraction-limited volume. Coupling super-resolution fluorescence microscopy and FRET has been a challenging and elusive task. Here, we present STED-FRET, a method of general applicability to obtain super-resolved energy transfer images. In addition to higher spatial resolution, STED-FRET provides a more accurate quantification of interaction and has the capacity of suppressing contributions of noninteracting partners, which are otherwise masked by averaging in conventional imaging. The method capabilities were first demonstrated on DNA-origami model systems, verified on uniformly double-labeled microtubules, and then utilized to image biomolecular interactions in the membrane-associated periodic skeleton (MPS) of neurons.}, keywords = {Foundry Organic, Molecularly-Functionalized}, pubstate = {published}, tppubtype = {article} } Förster resonance energy transfer (FRET) imaging methods provide unique insight into the spatial distribution of energy transfer and (bio)molecular interaction events, though they deliver average information for an ensemble of events included in a diffraction-limited volume. Coupling super-resolution fluorescence microscopy and FRET has been a challenging and elusive task. Here, we present STED-FRET, a method of general applicability to obtain super-resolved energy transfer images. In addition to higher spatial resolution, STED-FRET provides a more accurate quantification of interaction and has the capacity of suppressing contributions of noninteracting partners, which are otherwise masked by averaging in conventional imaging. The method capabilities were first demonstrated on DNA-origami model systems, verified on uniformly double-labeled microtubules, and then utilized to image biomolecular interactions in the membrane-associated periodic skeleton (MPS) of neurons. |
| 203. | J Kussmann, H Laqua, C Ochsenfeld Highly Efficient Resolution-of-Identity Density Functional Theory Calculations on Central and Graphics Processing Units Journal Article Journal of Chemical Theory and Computation, 2021, ISSN: 1549-9618. Abstract | Links | Tags: Foundry Inorganic @article{, title = {Highly Efficient Resolution-of-Identity Density Functional Theory Calculations on Central and Graphics Processing Units}, author = {J Kussmann and H Laqua and C Ochsenfeld}, url = {https://doi.org/10.1021/acs.jctc.0c01252}, doi = {10.1021/acs.jctc.0c01252}, issn = {1549-9618}, year = {2021}, date = {2021-02-22}, journal = {Journal of Chemical Theory and Computation}, abstract = {We present an efficient method to evaluate Coulomb potential matrices using the resolution of identity approximation and semilocal exchange-correlation potentials on central (CPU) and graphics processing units (GPU). The new GPU-based RI-algorithm shows a high performance and ensures the favorable scaling with increasing basis set size as the conventional CPU-based method. Furthermore, our method is based on the J-engine algorithm [White; , Head-Gordon, J. Chem. Phys. 1996, 7, 2620], which allows for further optimizations that also provide a significant improvement of the corresponding CPU-based algorithm. Due to the increased performance for the Coulomb evaluation, the calculation of the exchange-correlation potential of density functional theory on CPUs quickly becomes a bottleneck to the overall computational time. Hence, we also present a GPU-based algorithm to evaluate the exchange-correlation terms, which results in an overall high-performance method for density functional calculations. The algorithms to evaluate the potential and nuclear derivative terms are discussed, and their performance on CPUs and GPUs is demonstrated for illustrative calculations.}, keywords = {Foundry Inorganic}, pubstate = {published}, tppubtype = {article} } We present an efficient method to evaluate Coulomb potential matrices using the resolution of identity approximation and semilocal exchange-correlation potentials on central (CPU) and graphics processing units (GPU). The new GPU-based RI-algorithm shows a high performance and ensures the favorable scaling with increasing basis set size as the conventional CPU-based method. Furthermore, our method is based on the J-engine algorithm [White; , Head-Gordon, J. Chem. Phys. 1996, 7, 2620], which allows for further optimizations that also provide a significant improvement of the corresponding CPU-based algorithm. Due to the increased performance for the Coulomb evaluation, the calculation of the exchange-correlation potential of density functional theory on CPUs quickly becomes a bottleneck to the overall computational time. Hence, we also present a GPU-based algorithm to evaluate the exchange-correlation terms, which results in an overall high-performance method for density functional calculations. The algorithms to evaluate the potential and nuclear derivative terms are discussed, and their performance on CPUs and GPUs is demonstrated for illustrative calculations. |
| 202. | M Peschel, P Kabacinski, D P Schwinger, E Thyrhaug, G Cerullo, T Bach, J Hauer, De R Vivie-Riedle Activation of 2-Cyclohexenone by BF3 Coordination: Mechanistic Insights from Theory and Experiment Journal Article Angewandte Chemie International Edition, n/a (n/a), 2021, ISSN: 1433-7851. Abstract | Links | Tags: Molecularly-Functionalized, Solid-Liquid @article{, title = {Activation of 2-Cyclohexenone by BF3 Coordination: Mechanistic Insights from Theory and Experiment}, author = {M Peschel and P Kabacinski and D P Schwinger and E Thyrhaug and G Cerullo and T Bach and J Hauer and De R Vivie-Riedle}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202016653}, doi = {https://doi.org/10.1002/anie.202016653}, issn = {1433-7851}, year = {2021}, date = {2021-02-17}, journal = {Angewandte Chemie International Edition}, volume = {n/a}, number = {n/a}, abstract = {Lewis acids have recently been recognized as catalysts enabling enantioselective photochemical transformations. Mechanistic studies on these systems are however rare, either due to their absorption at wavelengths shorter than 260 nm, or due to the limitations of theoretical dynamic studies for larger complexes. In this work, we overcome these challenges and employ sub-30-fs transient absorption in the UV, in combination with a highly accurate theoretical treatment on the XMS-CASPT2 level. We investigate 2-cyclohexenone and its complex to boron trifluoride and analyze the observed dynamics based on trajectory calculations including non-adiabatic coupling and intersystem crossing. This approach explains all ultrafast decay pathways observed in the complex. We show that the Lewis acid remains attached to the substrate in the triplet state, which in turn explains why chiral boron-based Lewis acids induce a high enantioselectivity in photocycloaddition reactions.}, keywords = {Molecularly-Functionalized, Solid-Liquid}, pubstate = {published}, tppubtype = {article} } Lewis acids have recently been recognized as catalysts enabling enantioselective photochemical transformations. Mechanistic studies on these systems are however rare, either due to their absorption at wavelengths shorter than 260 nm, or due to the limitations of theoretical dynamic studies for larger complexes. In this work, we overcome these challenges and employ sub-30-fs transient absorption in the UV, in combination with a highly accurate theoretical treatment on the XMS-CASPT2 level. We investigate 2-cyclohexenone and its complex to boron trifluoride and analyze the observed dynamics based on trajectory calculations including non-adiabatic coupling and intersystem crossing. This approach explains all ultrafast decay pathways observed in the complex. We show that the Lewis acid remains attached to the substrate in the triplet state, which in turn explains why chiral boron-based Lewis acids induce a high enantioselectivity in photocycloaddition reactions. |
| 201. | J Kröger, A Jiménez-Solano, G Savasci, P Rovó, I Moudrakovski, K Küster, H Schlomberg, H A Vignolo-González, V Duppel, L Grunenberg, C B Dayan, M Sitti, F Podjaski, C Ochsenfeld, B V Lotsch Advanced Energy Materials, 11 (6), pp. 2170028, 2021, ISSN: 1614-6832. Abstract | Links | Tags: Molecularly-Functionalized @article{, title = {Photocatalytic Hydrogen Evolution: Interfacial Engineering for Improved Photocatalysis in a Charge Storing 2D Carbon Nitride: Melamine Functionalized Poly(heptazine imide) (Adv. Energy Mater. 6/2021)}, author = {J Kr\"{o}ger and A Jim\'{e}nez-Solano and G Savasci and P Rov\'{o} and I Moudrakovski and K K\"{u}ster and H Schlomberg and H A Vignolo-Gonz\'{a}lez and V Duppel and L Grunenberg and C B Dayan and M Sitti and F Podjaski and C Ochsenfeld and B V Lotsch}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/aenm.202170028}, doi = {https://doi.org/10.1002/aenm.202170028}, issn = {1614-6832}, year = {2021}, date = {2021-02-11}, journal = {Advanced Energy Materials}, volume = {11}, number = {6}, pages = {2170028}, abstract = {In article number 2003016, Bettina V. Lotsch and co-workers demonstrate that covalent surface modifications of the 2D carbon nitride poly(heptazine imide) with melamine groups strongly influence its polarity and photo(electrochemical) properties. This potent tuning pathway also results in the boosting of photocatalytic hydrogen evolution due to increased donor interactions and enhanced hole extraction.}, keywords = {Molecularly-Functionalized}, pubstate = {published}, tppubtype = {article} } In article number 2003016, Bettina V. Lotsch and co-workers demonstrate that covalent surface modifications of the 2D carbon nitride poly(heptazine imide) with melamine groups strongly influence its polarity and photo(electrochemical) properties. This potent tuning pathway also results in the boosting of photocatalytic hydrogen evolution due to increased donor interactions and enhanced hole extraction. |
| 200. | K Trofymchuk, V Glembockyte, L Grabenhorst, F Steiner, C Vietz, C Close, M Pfeiffer, L Richter, M L Schütte, F Selbach, R Yaadav, J Zähringer, Q Wei, A Ozcan, B Lalkens, G P Acuna, P Tinnefeld Addressable nanoantennas with cleared hotspots for single-molecule detection on a portable smartphone microscope Journal Article Nature Communications, 12 (1), pp. 950, 2021, ISSN: 2041-1723. Abstract | Links | Tags: Molecularly-Functionalized @article{, title = {Addressable nanoantennas with cleared hotspots for single-molecule detection on a portable smartphone microscope}, author = {K Trofymchuk and V Glembockyte and L Grabenhorst and F Steiner and C Vietz and C Close and M Pfeiffer and L Richter and M L Sch\"{u}tte and F Selbach and R Yaadav and J Z\"{a}hringer and Q Wei and A Ozcan and B Lalkens and G P Acuna and P Tinnefeld}, url = {https://doi.org/10.1038/s41467-021-21238-9}, doi = {10.1038/s41467-021-21238-9}, issn = {2041-1723}, year = {2021}, date = {2021-02-11}, journal = {Nature Communications}, volume = {12}, number = {1}, pages = {950}, abstract = {The advent of highly sensitive photodetectors and the development of photostabilization strategies made detecting the fluorescence of single molecules a routine task in many labs around the world. However, to this day, this process requires cost-intensive optical instruments due to the truly nanoscopic signal of a single emitter. Simplifying single-molecule detection would enable many exciting applications, e.g., in point-of-care diagnostic settings, where costly equipment would be prohibitive. Here, we introduce addressable NanoAntennas with Cleared HOtSpots (NACHOS) that are scaffolded by DNA origami nanostructures and can be specifically tailored for the incorporation of bioassays. Single emitters placed in NACHOS emit up to 461-fold (average of 89 ± 7-fold) brighter enabling their detection with a customary smartphone camera and an 8-US-dollar objective lens. To prove the applicability of our system, we built a portable, battery-powered smartphone microscope and successfully carried out an exemplary single-molecule detection assay for DNA specific to antibiotic-resistant Klebsiella pneumonia on the road.}, keywords = {Molecularly-Functionalized}, pubstate = {published}, tppubtype = {article} } The advent of highly sensitive photodetectors and the development of photostabilization strategies made detecting the fluorescence of single molecules a routine task in many labs around the world. However, to this day, this process requires cost-intensive optical instruments due to the truly nanoscopic signal of a single emitter. Simplifying single-molecule detection would enable many exciting applications, e.g., in point-of-care diagnostic settings, where costly equipment would be prohibitive. Here, we introduce addressable NanoAntennas with Cleared HOtSpots (NACHOS) that are scaffolded by DNA origami nanostructures and can be specifically tailored for the incorporation of bioassays. Single emitters placed in NACHOS emit up to 461-fold (average of 89 ± 7-fold) brighter enabling their detection with a customary smartphone camera and an 8-US-dollar objective lens. To prove the applicability of our system, we built a portable, battery-powered smartphone microscope and successfully carried out an exemplary single-molecule detection assay for DNA specific to antibiotic-resistant Klebsiella pneumonia on the road. |
| 199. | S Wang, Yousefi A A Amin, L Wu, M Cao, Q Zhang, T Ameri Perovskite Nanocrystals: Synthesis, Stability, and Optoelectronic Applications Journal Article Small Structures, n/a (n/a), pp. 2000124, 2021, ISSN: 2688-4062. Abstract | Links | Tags: Foundry Inorganic @article{, title = {Perovskite Nanocrystals: Synthesis, Stability, and Optoelectronic Applications}, author = {S Wang and Yousefi A A Amin and L Wu and M Cao and Q Zhang and T Ameri}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/sstr.202000124}, doi = {https://doi.org/10.1002/sstr.202000124}, issn = {2688-4062}, year = {2021}, date = {2021-02-07}, journal = {Small Structures}, volume = {n/a}, number = {n/a}, pages = {2000124}, abstract = {Metal halide perovskite (MHP) materials, named as the game changers, have attracted researchers’ attention worldwide for over a decade. Among them, nanometer-scale perovskite nanocrystals (PNCs) have exhibited attractive photophysical properties, such as tunable bandgaps, narrow emission, strong light-absorption coefficients, and high defect tolerance, because they combined the excellent optoelectronic properties of bulk perovskite materials with strong quantum confinement effects of the nanoscale. These materials possess a great potential to be applied in the optoelectronic devices. For commercial applications in devices like solar cells (SCs), light-emitting diodes (LEDs), and photodetectors (PDs), the stability of PNCs against ambient atmosphere like oxygen and moisture, as well as light and high temperature is crucial. Herein, the synthetic methods and stability issues of the PNCs are introduced first, followed by the introduction of the strategies for improving their stability by encapsulation. The applications of PNCs in various optoelectronic devices are then briefly presented. Finally, the remained challenges in improving the stability of PNCs toward the PNC-based optoelectronics with high performance and great durability are addressed.}, keywords = {Foundry Inorganic}, pubstate = {published}, tppubtype = {article} } Metal halide perovskite (MHP) materials, named as the game changers, have attracted researchers’ attention worldwide for over a decade. Among them, nanometer-scale perovskite nanocrystals (PNCs) have exhibited attractive photophysical properties, such as tunable bandgaps, narrow emission, strong light-absorption coefficients, and high defect tolerance, because they combined the excellent optoelectronic properties of bulk perovskite materials with strong quantum confinement effects of the nanoscale. These materials possess a great potential to be applied in the optoelectronic devices. For commercial applications in devices like solar cells (SCs), light-emitting diodes (LEDs), and photodetectors (PDs), the stability of PNCs against ambient atmosphere like oxygen and moisture, as well as light and high temperature is crucial. Herein, the synthetic methods and stability issues of the PNCs are introduced first, followed by the introduction of the strategies for improving their stability by encapsulation. The applications of PNCs in various optoelectronic devices are then briefly presented. Finally, the remained challenges in improving the stability of PNCs toward the PNC-based optoelectronics with high performance and great durability are addressed. |
| 198. | A Henning, J D Bartl, A Zeidler, S Qian, O Bienek, C-M Jiang, C Paulus, B Rieger, M Stutzmann, I D Sharp Aluminum Oxide at the Monolayer Limit via Oxidant-free Plasma-Assisted Atomic Layer Deposition on GaN Journal Article arXiv preprint arXiv:2102.03642, 2021. Tags: Foundry Inorganic @article{, title = {Aluminum Oxide at the Monolayer Limit via Oxidant-free Plasma-Assisted Atomic Layer Deposition on GaN}, author = {A Henning and J D Bartl and A Zeidler and S Qian and O Bienek and C-M Jiang and C Paulus and B Rieger and M Stutzmann and I D Sharp}, year = {2021}, date = {2021-02-06}, journal = {arXiv preprint arXiv:2102.03642}, keywords = {Foundry Inorganic}, pubstate = {published}, tppubtype = {article} } |
| 197. | L Katzenmeier, S Helmer, S Braxmeier, E Knobbe, A S Bandarenka Properties of the Space Charge Layers Formed in Li-Ion Conducting Glass Ceramics Journal Article ACS Applied Materials & Interfaces, 13 (4), pp. 5853-5860, 2021, ISSN: 1944-8244. Abstract | Links | Tags: Solid-Solid @article{, title = {Properties of the Space Charge Layers Formed in Li-Ion Conducting Glass Ceramics}, author = {L Katzenmeier and S Helmer and S Braxmeier and E Knobbe and A S Bandarenka}, url = {https://doi.org/10.1021/acsami.0c21304}, doi = {10.1021/acsami.0c21304}, issn = {1944-8244}, year = {2021}, date = {2021-02-03}, journal = {ACS Applied Materials & Interfaces}, volume = {13}, number = {4}, pages = {5853-5860}, abstract = {For years, the space charge layer formation in Li-conducting solid electrolytes and its relevance to so-called all solid-state batteries have been controversially discussed from experimental and theoretical perspectives. In this work, we observe the phenomenon of space charge layer formation using impedance spectroscopy at different electrode polarizations. We analyze the properties of these space charge layers using a physical equivalent circuit describing the response of the solid electrolytes and solid/solid electrified interfaces under blocking conditions. The elements corresponding to the interfacial layers are identified and analyzed with different electrode metals and applied biases. The effective thickness of the space charge layer was calculated to be ∼60 nm at a bias potential of 1 V. In addition, it was possible to estimate the relative permittivity of the electrolytes, specific resistance of the space charge layer, and the effective thickness of the electric double layer (∼0.7 nm).}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } For years, the space charge layer formation in Li-conducting solid electrolytes and its relevance to so-called all solid-state batteries have been controversially discussed from experimental and theoretical perspectives. In this work, we observe the phenomenon of space charge layer formation using impedance spectroscopy at different electrode polarizations. We analyze the properties of these space charge layers using a physical equivalent circuit describing the response of the solid electrolytes and solid/solid electrified interfaces under blocking conditions. The elements corresponding to the interfacial layers are identified and analyzed with different electrode metals and applied biases. The effective thickness of the space charge layer was calculated to be ∼60 nm at a bias potential of 1 V. In addition, it was possible to estimate the relative permittivity of the electrolytes, specific resistance of the space charge layer, and the effective thickness of the electric double layer (∼0.7 nm). |
| 196. | M Ogura, D Han, M M Pointner, L S Junkers, S S Rudel, W Schnick, H Ebert Electronic properties of semiconducting Zn(Si, Ge, Sn)N2 alloys Journal Article Physical Review Materials, 5 (2), pp. 024601, 2021. Links | Tags: Solid-Solid @article{, title = {Electronic properties of semiconducting Zn(Si, Ge, Sn)N2 alloys}, author = {M Ogura and D Han and M M Pointner and L S Junkers and S S Rudel and W Schnick and H Ebert}, url = {https://link.aps.org/doi/10.1103/PhysRevMaterials.5.024601}, doi = {10.1103/PhysRevMaterials.5.024601}, year = {2021}, date = {2021-02-02}, journal = {Physical Review Materials}, volume = {5}, number = {2}, pages = {024601}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } |
| 195. | F Pielnhofer, L Diehl, A Jiménez-Solano, A Bussmann-Holder, J C Schön, B V Lotsch Examination of possible high-pressure candidates of SnTiO3: The search for novel ferroelectric materials Journal Article APL Materials, 9 (2), pp. 021103, 2021. Links | Tags: Solid-Solid @article{, title = {Examination of possible high-pressure candidates of SnTiO3: The search for novel ferroelectric materials}, author = {F Pielnhofer and L Diehl and A Jim\'{e}nez-Solano and A Bussmann-Holder and J C Sch\"{o}n and B V Lotsch}, url = {https://aip.scitation.org/doi/abs/10.1063/5.0029968}, doi = {10.1063/5.0029968}, year = {2021}, date = {2021-02-02}, journal = {APL Materials}, volume = {9}, number = {2}, pages = {021103}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } |
| 194. | M R P Pielmeier, T Nilges Formation Mechanisms for Phosphorene and SnIP Journal Article Angewandte Chemie International Edition, n/a (n/a), 2021, ISSN: 1433-7851. Abstract | Links | Tags: Foundry Inorganic @article{, title = {Formation Mechanisms for Phosphorene and SnIP}, author = {M R P Pielmeier and T Nilges}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202016257}, doi = {https://doi.org/10.1002/anie.202016257}, issn = {1433-7851}, year = {2021}, date = {2021-01-29}, journal = {Angewandte Chemie International Edition}, volume = {n/a}, number = {n/a}, abstract = {Abstract Phosphorene\textemdashthe monolayered material of the element allotrope black phosphorus (Pblack)\textemdashand SnIP are 2D and 1D semiconductors with intriguing physical properties. Pblack and SnIP have in common that they can be synthesized via short way transport or mineralization using tin, tin(IV) iodide and amorphous red phosphorus. This top-down approach is the most important access route to phosphorene. The two preparation routes are closely connected and differ mainly in reaction temperature and molar ratios of starting materials. Many speculative intermediates or activator side phases have been postulated especially for top-down Pblack/phosphorene synthesis, such as Hittorf's phosphorus or Sn24P19.3I8 clathrate. The importance of phosphorus-based 2D and 1D materials for energy conversion, storage, and catalysis inspired us to elucidate the formation mechanisms of these two compounds. Herein, we report on the reaction mechanisms of Pblack/phosphorene and SnIP from P4 and SnI2 via direct gas phase formation.}, keywords = {Foundry Inorganic}, pubstate = {published}, tppubtype = {article} } Abstract Phosphorene—the monolayered material of the element allotrope black phosphorus (Pblack)—and SnIP are 2D and 1D semiconductors with intriguing physical properties. Pblack and SnIP have in common that they can be synthesized via short way transport or mineralization using tin, tin(IV) iodide and amorphous red phosphorus. This top-down approach is the most important access route to phosphorene. The two preparation routes are closely connected and differ mainly in reaction temperature and molar ratios of starting materials. Many speculative intermediates or activator side phases have been postulated especially for top-down Pblack/phosphorene synthesis, such as Hittorf's phosphorus or Sn24P19.3I8 clathrate. The importance of phosphorus-based 2D and 1D materials for energy conversion, storage, and catalysis inspired us to elucidate the formation mechanisms of these two compounds. Herein, we report on the reaction mechanisms of Pblack/phosphorene and SnIP from P4 and SnI2 via direct gas phase formation. |
| 193. | D Han, H Ebert Identification of Potential Optoelectronic Applications for Metal Thiophosphates Journal Article ACS Applied Materials & Interfaces, 13 (3), pp. 3836-3844, 2021, ISSN: 1944-8244. Abstract | Links | Tags: Solid-Solid @article{, title = {Identification of Potential Optoelectronic Applications for Metal Thiophosphates}, author = {D Han and H Ebert}, url = {https://doi.org/10.1021/acsami.0c17818}, doi = {10.1021/acsami.0c17818}, issn = {1944-8244}, year = {2021}, date = {2021-01-27}, journal = {ACS Applied Materials & Interfaces}, volume = {13}, number = {3}, pages = {3836-3844}, abstract = {Metal thiophosphates are a large family of compounds that received far less attention than conventional chalcogenides. Recently, however, metal thiophosphates arouse research interest in regard of energy harvesting and conversion due to their structural and chemical diversity. Nevertheless, there remain many unexplored metal thiophosphates. Here, we performed a comprehensive investigation on the electronic and optoelectronic properties of a series of metal thiophosphates using first-principles calculations and identified several highly promising compounds as p-type transparent conductors, photovoltaic absorbers, and single visible-light-driven photocatalysts for water splitting. Our investigation reveals the intrinsic features of a series of typical metal thiophosphates, identifies their new optoelectronic applications, and validates that metal thiophosphates are promising materials deserving exploration.}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } Metal thiophosphates are a large family of compounds that received far less attention than conventional chalcogenides. Recently, however, metal thiophosphates arouse research interest in regard of energy harvesting and conversion due to their structural and chemical diversity. Nevertheless, there remain many unexplored metal thiophosphates. Here, we performed a comprehensive investigation on the electronic and optoelectronic properties of a series of metal thiophosphates using first-principles calculations and identified several highly promising compounds as p-type transparent conductors, photovoltaic absorbers, and single visible-light-driven photocatalysts for water splitting. Our investigation reveals the intrinsic features of a series of typical metal thiophosphates, identifies their new optoelectronic applications, and validates that metal thiophosphates are promising materials deserving exploration. |
| 192. | A Hötger, J Klein, K Barthelmi, L Sigl, F Sigger, W Männer, S Gyger, M Florian, M Lorke, F Jahnke, T Taniguchi, K Watanabe, K D Jöns, U Wurstbauer, C Kastl, K Müller, J J Finley, A W Holleitner Gate-Switchable Arrays of Quantum Light Emitters in Contacted Monolayer MoS2 van der Waals Heterodevices Journal Article Nano Letters, 21 (2), pp. 1040-1046, 2021, ISSN: 1530-6984. Abstract | Links | Tags: Solid-Solid @article{, title = {Gate-Switchable Arrays of Quantum Light Emitters in Contacted Monolayer MoS2 van der Waals Heterodevices}, author = {A H\"{o}tger and J Klein and K Barthelmi and L Sigl and F Sigger and W M\"{a}nner and S Gyger and M Florian and M Lorke and F Jahnke and T Taniguchi and K Watanabe and K D J\"{o}ns and U Wurstbauer and C Kastl and K M\"{u}ller and J J Finley and A W Holleitner}, url = {https://doi.org/10.1021/acs.nanolett.0c04222}, doi = {10.1021/acs.nanolett.0c04222}, issn = {1530-6984}, year = {2021}, date = {2021-01-27}, journal = {Nano Letters}, volume = {21}, number = {2}, pages = {1040-1046}, abstract = {We demonstrate electrostatic switching of individual, site-selectively generated matrices of single photon emitters (SPEs) in MoS2 van der Waals heterodevices. We contact monolayers of MoS2 in field-effect devices with graphene gates and hexagonal boron nitride as the dielectric and graphite as bottom gates. After the assembly of such gate-tunable heterodevices, we demonstrate how arrays of defects, that serve as quantum emitters, can be site-selectively generated in the monolayer MoS2 by focused helium ion irradiation. The SPEs are sensitive to the charge carrier concentration in the MoS2 and switch on and off similar to the neutral exciton in MoS2 for moderate electron doping. The demonstrated scheme is a first step for producing scalable, gate-addressable, and gate-switchable arrays of quantum light emitters in MoS2 heterostacks.}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } We demonstrate electrostatic switching of individual, site-selectively generated matrices of single photon emitters (SPEs) in MoS2 van der Waals heterodevices. We contact monolayers of MoS2 in field-effect devices with graphene gates and hexagonal boron nitride as the dielectric and graphite as bottom gates. After the assembly of such gate-tunable heterodevices, we demonstrate how arrays of defects, that serve as quantum emitters, can be site-selectively generated in the monolayer MoS2 by focused helium ion irradiation. The SPEs are sensitive to the charge carrier concentration in the MoS2 and switch on and off similar to the neutral exciton in MoS2 for moderate electron doping. The demonstrated scheme is a first step for producing scalable, gate-addressable, and gate-switchable arrays of quantum light emitters in MoS2 heterostacks. |
| 191. | J Klein, L Sigl, S Gyger, K Barthelmi, M Florian, S Rey, T Taniguchi, K Watanabe, F Jahnke, C Kastl, V Zwiller, K D Jöns, K Müller, U Wurstbauer, J J Finley, A W Holleitner Engineering the Luminescence and Generation of Individual Defect Emitters in Atomically Thin MoS2 Journal Article ACS Photonics, 2021. Abstract | Links | Tags: Solid-Solid @article{, title = {Engineering the Luminescence and Generation of Individual Defect Emitters in Atomically Thin MoS2}, author = {J Klein and L Sigl and S Gyger and K Barthelmi and M Florian and S Rey and T Taniguchi and K Watanabe and F Jahnke and C Kastl and V Zwiller and K D J\"{o}ns and K M\"{u}ller and U Wurstbauer and J J Finley and A W Holleitner}, url = {https://doi.org/10.1021/acsphotonics.0c01907}, doi = {10.1021/acsphotonics.0c01907}, year = {2021}, date = {2021-01-21}, journal = {ACS Photonics}, abstract = {We demonstrate the on-demand creation and positioning of photon emitters in atomically thin MoS2 with very narrow ensemble broadening and negligible background luminescence. Focused helium-ion beam irradiation creates 100s to 1000s of such mono-typical emitters at specific positions in the MoS2 monolayers. Individually measured photon emitters show antibunching behavior with a g2(0) ∼ 0.23 and 0.27. From a statistical analysis, we extract the creation yield of the He-ion induced photon emitters in MoS2 as a function of the exposed area, as well as the total yield of single emitters as a function of the number of He ions when single spots are irradiated by He ions. We reach probabilities as high as 18% for the generation of individual and spectrally clean photon emitters per irradiated single site. Our results firmly establish 2D materials as a platform for photon emitters with unprecedented control of position as well as photophysical properties owing to the all-interfacial nature.}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } We demonstrate the on-demand creation and positioning of photon emitters in atomically thin MoS2 with very narrow ensemble broadening and negligible background luminescence. Focused helium-ion beam irradiation creates 100s to 1000s of such mono-typical emitters at specific positions in the MoS2 monolayers. Individually measured photon emitters show antibunching behavior with a g2(0) ∼ 0.23 and 0.27. From a statistical analysis, we extract the creation yield of the He-ion induced photon emitters in MoS2 as a function of the exposed area, as well as the total yield of single emitters as a function of the number of He ions when single spots are irradiated by He ions. We reach probabilities as high as 18% for the generation of individual and spectrally clean photon emitters per irradiated single site. Our results firmly establish 2D materials as a platform for photon emitters with unprecedented control of position as well as photophysical properties owing to the all-interfacial nature. |
| 190. | X Song, L Hou, R Guo, Q Wei, L Yang, X Jiang, S Tu, A Zhang, Z Kan, W Tang, G Xing, P Müller-Buschbaum ACS Applied Materials & Interfaces, 13 (2), pp. 2961-2970, 2021, ISSN: 1944-8244. Abstract | Links | Tags: Foundry Inorganic @article{, title = {Synergistic Interplay between Asymmetric Backbone Conformation, Molecular Aggregation, and Charge-Carrier Dynamics in Fused-Ring Electron Acceptor-Based Bulk Heterojunction Solar Cells}, author = {X Song and L Hou and R Guo and Q Wei and L Yang and X Jiang and S Tu and A Zhang and Z Kan and W Tang and G Xing and P M\"{u}ller-Buschbaum}, url = {https://doi.org/10.1021/acsami.0c19700}, doi = {10.1021/acsami.0c19700}, issn = {1944-8244}, year = {2021}, date = {2021-01-20}, journal = {ACS Applied Materials & Interfaces}, volume = {13}, number = {2}, pages = {2961-2970}, abstract = {Asymmetric fused-ring electron acceptors (a-FREAs) have proved to be a promising type of electron acceptor for high-performance organic solar cells (OSCs). However, the relationship among molecular structures of a-FREAs and their nanoscale morphology, charge-carrier dynamics, and device performance remains unclear. In this contribution, two FREAs differing in conjugated backbone geometry with an asymmetric conformation (IPT-2F) or symmetric one (INPIC-2F) are selected to systematically explore the superiorities of the asymmetric conformation. Despite the frailer extinction coefficient and weaker crystallinity, IPT-2F shows stronger dipole interactions in the asymmetrical backbone, which would induce a closer lamellar packing than that of the symmetrical counterpart. Using PBDB-T as the electron donor, the IPT-2F-based OSCs achieve the best power conversion efficiency of 14.0%, which is ca. 67% improvement compared to the INPIC-2F-based ones (8.37%), resulting from a simultaneously increased short-circuited current density (Jsc) and fill factor. Systematical investigations on optoelectronic and morphological properties show that the asymmetric conformation-structured IPT-2F exhibits better miscibility with the polymer donor to induce a favorable blend ordering with small domain sizes and suitable phase separation compared to the INPIC-2F symmetric molecule. This facilitates an efficient charge generation and transport, inhibits charge-carrier recombination, and promotes valid charge extraction in IPT-2F-based devices.}, keywords = {Foundry Inorganic}, pubstate = {published}, tppubtype = {article} } Asymmetric fused-ring electron acceptors (a-FREAs) have proved to be a promising type of electron acceptor for high-performance organic solar cells (OSCs). However, the relationship among molecular structures of a-FREAs and their nanoscale morphology, charge-carrier dynamics, and device performance remains unclear. In this contribution, two FREAs differing in conjugated backbone geometry with an asymmetric conformation (IPT-2F) or symmetric one (INPIC-2F) are selected to systematically explore the superiorities of the asymmetric conformation. Despite the frailer extinction coefficient and weaker crystallinity, IPT-2F shows stronger dipole interactions in the asymmetrical backbone, which would induce a closer lamellar packing than that of the symmetrical counterpart. Using PBDB-T as the electron donor, the IPT-2F-based OSCs achieve the best power conversion efficiency of 14.0%, which is ca. 67% improvement compared to the INPIC-2F-based ones (8.37%), resulting from a simultaneously increased short-circuited current density (Jsc) and fill factor. Systematical investigations on optoelectronic and morphological properties show that the asymmetric conformation-structured IPT-2F exhibits better miscibility with the polymer donor to induce a favorable blend ordering with small domain sizes and suitable phase separation compared to the INPIC-2F symmetric molecule. This facilitates an efficient charge generation and transport, inhibits charge-carrier recombination, and promotes valid charge extraction in IPT-2F-based devices. |
| 189. | X Dong, H Li, Z Jiang, T Grünleitner, İ Güler, J Dong, K Wang, M H Köhler, M Jakobi, B H Menze, A K Yetisen, I D Sharp, A V Stier, J J Finley, A W Koch 3D Deep Learning Enables Accurate Layer Mapping of 2D Materials Journal Article ACS Nano, 15 (2), pp. 3139-3151, 2021, ISSN: 1936-0851. Abstract | Links | Tags: Foundry Inorganic, Solid-Solid @article{, title = {3D Deep Learning Enables Accurate Layer Mapping of 2D Materials}, author = {X Dong and H Li and Z Jiang and T Gr\"{u}nleitner and \.{I} G\"{u}ler and J Dong and K Wang and M H K\"{o}hler and M Jakobi and B H Menze and A K Yetisen and I D Sharp and A V Stier and J J Finley and A W Koch}, url = {https://doi.org/10.1021/acsnano.0c09685}, doi = {10.1021/acsnano.0c09685}, issn = {1936-0851}, year = {2021}, date = {2021-01-19}, journal = {ACS Nano}, volume = {15}, number = {2}, pages = {3139-3151}, abstract = {Layered, two-dimensional (2D) materials are promising for next-generation photonics devices. Typically, the thickness of mechanically cleaved flakes and chemical vapor deposited thin films is distributed randomly over a large area, where accurate identification of atomic layer numbers is time-consuming. Hyperspectral imaging microscopy yields spectral information that can be used to distinguish the spectral differences of varying thickness specimens. However, its spatial resolution is relatively low due to the spectral imaging nature. In this work, we present a 3D deep learning solution called DALM (deep-learning-enabled atomic layer mapping) to merge hyperspectral reflection images (high spectral resolution) and RGB images (high spatial resolution) for the identification and segmentation of MoS2 flakes with mono-, bi-, tri-, and multilayer thicknesses. DALM is trained on a small set of labeled images, automatically predicts layer distributions and segments individual layers with high accuracy, and shows robustness to illumination and contrast variations. Further, we show its advantageous performance over the state-of-the-art model that is solely based on RGB microscope images. This AI-supported technique with high speed, spatial resolution, and accuracy allows for reliable computer-aided identification of atomically thin materials.}, keywords = {Foundry Inorganic, Solid-Solid}, pubstate = {published}, tppubtype = {article} } Layered, two-dimensional (2D) materials are promising for next-generation photonics devices. Typically, the thickness of mechanically cleaved flakes and chemical vapor deposited thin films is distributed randomly over a large area, where accurate identification of atomic layer numbers is time-consuming. Hyperspectral imaging microscopy yields spectral information that can be used to distinguish the spectral differences of varying thickness specimens. However, its spatial resolution is relatively low due to the spectral imaging nature. In this work, we present a 3D deep learning solution called DALM (deep-learning-enabled atomic layer mapping) to merge hyperspectral reflection images (high spectral resolution) and RGB images (high spatial resolution) for the identification and segmentation of MoS2 flakes with mono-, bi-, tri-, and multilayer thicknesses. DALM is trained on a small set of labeled images, automatically predicts layer distributions and segments individual layers with high accuracy, and shows robustness to illumination and contrast variations. Further, we show its advantageous performance over the state-of-the-art model that is solely based on RGB microscope images. This AI-supported technique with high speed, spatial resolution, and accuracy allows for reliable computer-aided identification of atomically thin materials. |
| 188. | M M Petrić, M Kremser, M Barbone, Y Qin, Y Sayyad, Y Shen, S Tongay, J J Finley, A R Botello-Méndez, K Müller Raman spectrum of Janus transition metal dichalcogenide monolayers WSSe and MoSSe Journal Article Physical Review B, 103 (3), pp. 035414, 2021. Links | Tags: Foundry Inorganic, Solid-Solid @article{, title = {Raman spectrum of Janus transition metal dichalcogenide monolayers WSSe and MoSSe}, author = {M M Petri\'{c} and M Kremser and M Barbone and Y Qin and Y Sayyad and Y Shen and S Tongay and J J Finley and A R Botello-M\'{e}ndez and K M\"{u}ller}, url = {https://link.aps.org/doi/10.1103/PhysRevB.103.035414}, doi = {10.1103/PhysRevB.103.035414}, year = {2021}, date = {2021-01-15}, journal = {Physical Review B}, volume = {103}, number = {3}, pages = {035414}, keywords = {Foundry Inorganic, Solid-Solid}, pubstate = {published}, tppubtype = {article} } |
| 187. | L A Masullo, F Steiner, J Zähringer, L F Lopez, J Bohlen, L Richter, F Cole, P Tinnefeld, F D Stefani Pulsed Interleaved MINFLUX Journal Article Nano Letters, 21 (1), pp. 840-846, 2021, ISSN: 1530-6984. Abstract | Links | Tags: Molecularly-Functionalized @article{, title = {Pulsed Interleaved MINFLUX}, author = {L A Masullo and F Steiner and J Z\"{a}hringer and L F Lopez and J Bohlen and L Richter and F Cole and P Tinnefeld and F D Stefani}, url = {https://doi.org/10.1021/acs.nanolett.0c04600}, doi = {10.1021/acs.nanolett.0c04600}, issn = {1530-6984}, year = {2021}, date = {2021-01-13}, journal = {Nano Letters}, volume = {21}, number = {1}, pages = {840-846}, abstract = {We introduce p-MINFLUX, a new implementation of the highly photon-efficient single-molecule localization method with a simplified experimental setup and additional fluorescence lifetime information. In contrast to the original MINFLUX implementation, p-MINFLUX uses interleaved laser pulses to deliver the doughnut-shaped excitation foci at a maximum repetition rate. Using both static and dynamic DNA origami model systems, we demonstrate the performance of p-MINFLUX for single-molecule localization nanoscopy and tracking, respectively. p-MINFLUX delivers 1\textendash2 nm localization precision with 2000\textendash1000 photon counts. In addition, p-MINFLUX gives access to the fluorescence lifetime enabling multiplexing and super-resolved lifetime imaging. p-MINFLUX should help to unlock the full potential of innovative single-molecule localization schemes.}, keywords = {Molecularly-Functionalized}, pubstate = {published}, tppubtype = {article} } We introduce p-MINFLUX, a new implementation of the highly photon-efficient single-molecule localization method with a simplified experimental setup and additional fluorescence lifetime information. In contrast to the original MINFLUX implementation, p-MINFLUX uses interleaved laser pulses to deliver the doughnut-shaped excitation foci at a maximum repetition rate. Using both static and dynamic DNA origami model systems, we demonstrate the performance of p-MINFLUX for single-molecule localization nanoscopy and tracking, respectively. p-MINFLUX delivers 1–2 nm localization precision with 2000–1000 photon counts. In addition, p-MINFLUX gives access to the fluorescence lifetime enabling multiplexing and super-resolved lifetime imaging. p-MINFLUX should help to unlock the full potential of innovative single-molecule localization schemes. |
| 186. | P Soubelet, J Klein, J Wierzbowski, R Silvioli, F Sigger, A V Stier, K Gallo, J J Finley Charged Exciton Kinetics in Monolayer MoSe2 near Ferroelectric Domain Walls in Periodically Poled LiNbO3 Journal Article Nano Letters, 21 (2), pp. 959-966, 2021, ISSN: 1530-6984. Abstract | Links | Tags: Foundry Inorganic, Solid-Solid @article{, title = {Charged Exciton Kinetics in Monolayer MoSe2 near Ferroelectric Domain Walls in Periodically Poled LiNbO3}, author = {P Soubelet and J Klein and J Wierzbowski and R Silvioli and F Sigger and A V Stier and K Gallo and J J Finley}, url = {https://doi.org/10.1021/acs.nanolett.0c03810}, doi = {10.1021/acs.nanolett.0c03810}, issn = {1530-6984}, year = {2021}, date = {2021-01-11}, journal = {Nano Letters}, volume = {21}, number = {2}, pages = {959-966}, abstract = {Monolayer semiconducting transition metal dichalcogenides are a strongly emergent platform for exploring quantum phenomena in condensed matter, building novel optoelectronic devices with enhanced functionalities. Because of their atomic thickness, their excitonic optical response is highly sensitive to their dielectric environment. In this work, we explore the optical properties of monolayer thick MoSe2 straddling domain wall boundaries in periodically poled LiNbO3. Spatially resolved photoluminescence experiments reveal spatial sorting of charge and photogenerated neutral and charged excitons across the boundary. Our results reveal evidence for extremely large in-plane electric fields of ≃4000 kV/cm at the domain wall whose effect is manifested in exciton dissociation and routing of free charges and trions toward oppositely poled domains and a nonintuitive spatial intensity dependence. By modeling our result using drift-diffusion and continuity equations, we obtain excellent qualitative agreement with our observations and have explained the observed spatial luminescence modulation using realistic material parameters.}, keywords = {Foundry Inorganic, Solid-Solid}, pubstate = {published}, tppubtype = {article} } Monolayer semiconducting transition metal dichalcogenides are a strongly emergent platform for exploring quantum phenomena in condensed matter, building novel optoelectronic devices with enhanced functionalities. Because of their atomic thickness, their excitonic optical response is highly sensitive to their dielectric environment. In this work, we explore the optical properties of monolayer thick MoSe2 straddling domain wall boundaries in periodically poled LiNbO3. Spatially resolved photoluminescence experiments reveal spatial sorting of charge and photogenerated neutral and charged excitons across the boundary. Our results reveal evidence for extremely large in-plane electric fields of ≃4000 kV/cm at the domain wall whose effect is manifested in exciton dissociation and routing of free charges and trions toward oppositely poled domains and a nonintuitive spatial intensity dependence. By modeling our result using drift-diffusion and continuity equations, we obtain excellent qualitative agreement with our observations and have explained the observed spatial luminescence modulation using realistic material parameters. |
| 185. | M Wörle, A W Holleitner, R Kienberger, H Iglev Ultrafast hot carrier relaxation in silicon monitored by phase-resolved transient absorption spectroscopy Journal Article arXiv preprint arXiv:2101.01439, 2021. Tags: Solid-Liquid @article{, title = {Ultrafast hot carrier relaxation in silicon monitored by phase-resolved transient absorption spectroscopy}, author = {M W\"{o}rle and A W Holleitner and R Kienberger and H Iglev}, year = {2021}, date = {2021-01-05}, journal = {arXiv preprint arXiv:2101.01439}, keywords = {Solid-Liquid}, pubstate = {published}, tppubtype = {article} } |
| 184. | L Shani, P Tinnefeld, Y Fleger, A Sharoni, B Y Shapiro, A Shaulov, O Gang, Y Yeshurun DNA origami based superconducting nanowires Journal Article AIP Advances, 11 (1), pp. 015130, 2021. Links | Tags: Foundry Organic @article{, title = {DNA origami based superconducting nanowires}, author = {L Shani and P Tinnefeld and Y Fleger and A Sharoni and B Y Shapiro and A Shaulov and O Gang and Y Yeshurun}, url = {https://doi.org/10.1063/5.0029781}, doi = {10.1063/5.0029781}, year = {2021}, date = {2021-01-01}, journal = {AIP Advances}, volume = {11}, number = {1}, pages = {015130}, keywords = {Foundry Organic}, pubstate = {published}, tppubtype = {article} } |
| 183. | L Kristina, H Alex, Markus H W., A Robin, Johannes B D., Ian S D., R Roberto, Dominik B Benjamin Surface NMR Using Quantum Sensors in Diamond Book 2021. Abstract | Links | Tags: Molecularly-Functionalized, Solid-Solid @book{, title = {Surface NMR Using Quantum Sensors in Diamond}, author = {L Kristina and H Alex and Markus H W. and A Robin and Johannes B D. and Ian S D. and R Roberto and Dominik B Benjamin}, url = {https://chemrxiv.org/articles/preprint/Surface_NMR_Using_Quantum_Sensors_in_Diamond/14269217}, doi = {10.26434/chemrxiv.14269217.v1}, year = {2021}, date = {2021-01-01}, abstract = {Characterization of the molecular properties of surfaces under ambient or chemically reactive conditions isa fundamental scientific challenge. Moreover, many traditional analytical techniques used for probing surfaces often lack dynamic or molecular selectivity, which limits their applicability for mechanistic and kinetic studies under realistic chemical conditions. Nuclear magnetic resonance spectroscopy (NMR) is a widely used technique and would be ideal for probing interfaces due to the molecular information it provides noninvasively. However, it lacks the sensitivity to probe the small number of spins at surfaces. Here, we use nitrogen vacancy (NV) centers in diamond as quantum sensors to optically detect nuclear magnetic resonance signals fromchemically modified aluminum oxide surfaces, prepared with atomic layer deposition (ALD). With the surfaceNV-NMR technique, we are able to monitor in real-time the formation kinetics of a self assembled monolayer (SAM) based on phosphonate anchoring chemistry to the surface. This demonstrates the capability of quan-tum sensors as a new surface-sensitive tool with sub-monolayer sensitivity for in-situ NMR analysis with theadditional advantage of a strongly reduced technical complexity.}, keywords = {Molecularly-Functionalized, Solid-Solid}, pubstate = {published}, tppubtype = {book} } Characterization of the molecular properties of surfaces under ambient or chemically reactive conditions isa fundamental scientific challenge. Moreover, many traditional analytical techniques used for probing surfaces often lack dynamic or molecular selectivity, which limits their applicability for mechanistic and kinetic studies under realistic chemical conditions. Nuclear magnetic resonance spectroscopy (NMR) is a widely used technique and would be ideal for probing interfaces due to the molecular information it provides noninvasively. However, it lacks the sensitivity to probe the small number of spins at surfaces. Here, we use nitrogen vacancy (NV) centers in diamond as quantum sensors to optically detect nuclear magnetic resonance signals fromchemically modified aluminum oxide surfaces, prepared with atomic layer deposition (ALD). With the surfaceNV-NMR technique, we are able to monitor in real-time the formation kinetics of a self assembled monolayer (SAM) based on phosphonate anchoring chemistry to the surface. This demonstrates the capability of quan-tum sensors as a new surface-sensitive tool with sub-monolayer sensitivity for in-situ NMR analysis with theadditional advantage of a strongly reduced technical complexity. |
| 182. | K Julia, J-S Alberto, S Gökcen, Vincent L Wing-Hei, D Viola, M Igor, K Kathrin, S Tanja, G Andreas, Marie S Luise, P Filip, O Christian, L Bettina 2021. Abstract | Links | Tags: Foundry Inorganic, Solid-Solid @book{, title = {Morphology Control in 2D Carbon Nitrides: Impact of Particle Size on Optoelectronic Properties and Photocatalysis}, author = {K Julia and J-S Alberto and S G\"{o}kcen and Vincent L Wing-Hei and D Viola and M Igor and K Kathrin and S Tanja and G Andreas and Marie S Luise and P Filip and O Christian and L Bettina}, url = {https://chemrxiv.org/articles/preprint/Morphology_Control_in_2D_Carbon_Nitrides_Impact_of_Particle_Size_on_Optoelectronic_Properties_and_Photocatalysis/14346194}, doi = {10.26434/chemrxiv.14346194.v1}, year = {2021}, date = {2021-01-01}, abstract = {The carbon nitride poly(heptazine imide), PHI, has recently emerged as a powerful 2D carbon nitride photocatalyst with intriguing charge storing ability. Yet, insights into how morphology, particle size and defects influence its photophysical properties are virtually absent. Here, ultrasonication is used to systematically tune the particle size as well as concentration of surface functional groups and study their impact. Enhanced photocatalytic activity correlates with an optimal amount of those defects that create shallow trap states in the optical band gap, promoting charge percolation, as evidenced by time-resolved photoluminescence spectroscopy, charge transport studies, and quantum-chemical calculations. Excessive amounts of terminal defects can act as recombination centers and hence, decrease the photocatalytic activity for hydrogen evolution. Re-agglomeration of small particles can, however, partially restore the photocatalytic activity. The type and amount of trap states at the surface can also influence the deposition of the co-catalyst Pt, which is used in hydrogen evolution experiments. Optimized conditions entail improved Pt distribution, as well as an enhanced wettability and colloidal stability. A description of the interplay between these effects is provided to obtain a holistic picture of the size\textendashproperty\textendashactivity relationship in nanoparticulate PHI-type carbon nitrides that can likely be generalized to related photocatalytic systems. }, keywords = {Foundry Inorganic, Solid-Solid}, pubstate = {published}, tppubtype = {book} } The carbon nitride poly(heptazine imide), PHI, has recently emerged as a powerful 2D carbon nitride photocatalyst with intriguing charge storing ability. Yet, insights into how morphology, particle size and defects influence its photophysical properties are virtually absent. Here, ultrasonication is used to systematically tune the particle size as well as concentration of surface functional groups and study their impact. Enhanced photocatalytic activity correlates with an optimal amount of those defects that create shallow trap states in the optical band gap, promoting charge percolation, as evidenced by time-resolved photoluminescence spectroscopy, charge transport studies, and quantum-chemical calculations. Excessive amounts of terminal defects can act as recombination centers and hence, decrease the photocatalytic activity for hydrogen evolution. Re-agglomeration of small particles can, however, partially restore the photocatalytic activity. The type and amount of trap states at the surface can also influence the deposition of the co-catalyst Pt, which is used in hydrogen evolution experiments. Optimized conditions entail improved Pt distribution, as well as an enhanced wettability and colloidal stability. A description of the interplay between these effects is provided to obtain a holistic picture of the size–property–activity relationship in nanoparticulate PHI-type carbon nitrides that can likely be generalized to related photocatalytic systems.<br> |
| 181. | E Cortés, L V Besteiro, A Alabastri, A Baldi, G Tagliabue, A Demetriadou, P Narang Challenges in Plasmonic Catalysis Journal Article ACS Nano, 14 (12), pp. 16202-16219, 2020, ISSN: 1936-0851. Abstract | Links | Tags: Solid-Solid @article{, title = {Challenges in Plasmonic Catalysis}, author = {E Cort\'{e}s and L V Besteiro and A Alabastri and A Baldi and G Tagliabue and A Demetriadou and P Narang}, url = {https://doi.org/10.1021/acsnano.0c08773}, doi = {10.1021/acsnano.0c08773}, issn = {1936-0851}, year = {2020}, date = {2020-12-22}, journal = {ACS Nano}, volume = {14}, number = {12}, pages = {16202-16219}, abstract = {The use of nanoplasmonics to control light and heat close to the thermodynamic limit enables exciting opportunities in the field of plasmonic catalysis. The decay of plasmonic excitations creates highly nonequilibrium distributions of hot carriers that can initiate or catalyze reactions through both thermal and nonthermal pathways. In this Perspective, we present the current understanding in the field of plasmonic catalysis, capturing vibrant debates in the literature, and discuss future avenues of exploration to overcome critical bottlenecks. Our Perspective spans first-principles theory and computation of correlated and far-from-equilibrium light\textendashmatter interactions, synthesis of new nanoplasmonic hybrids, and new steady-state and ultrafast spectroscopic probes of interactions in plasmonic catalysis, recognizing the key contributions of each discipline in realizing the promise of plasmonic catalysis. We conclude with our vision for fundamental and technological advances in the field of plasmon-driven chemical reactions in the coming years.}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } The use of nanoplasmonics to control light and heat close to the thermodynamic limit enables exciting opportunities in the field of plasmonic catalysis. The decay of plasmonic excitations creates highly nonequilibrium distributions of hot carriers that can initiate or catalyze reactions through both thermal and nonthermal pathways. In this Perspective, we present the current understanding in the field of plasmonic catalysis, capturing vibrant debates in the literature, and discuss future avenues of exploration to overcome critical bottlenecks. Our Perspective spans first-principles theory and computation of correlated and far-from-equilibrium light–matter interactions, synthesis of new nanoplasmonic hybrids, and new steady-state and ultrafast spectroscopic probes of interactions in plasmonic catalysis, recognizing the key contributions of each discipline in realizing the promise of plasmonic catalysis. We conclude with our vision for fundamental and technological advances in the field of plasmon-driven chemical reactions in the coming years. |
| 180. | N Keller, T Bein Optoelectronic processes in covalent organic frameworks Journal Article Chemical Society Reviews, 2020, ISSN: 0306-0012. Abstract | Links | Tags: Molecularly-Functionalized @article{, title = {Optoelectronic processes in covalent organic frameworks}, author = {N Keller and T Bein}, url = {http://dx.doi.org/10.1039/D0CS00793E}, doi = {10.1039/D0CS00793E}, issn = {0306-0012}, year = {2020}, date = {2020-12-17}, journal = {Chemical Society Reviews}, abstract = {Covalent organic frameworks (COFs) are crystalline porous materials constructed from molecular building blocks using diverse linkage chemistries. Their modular construction system allows not only for tailor-made design but also for an immense variety of building blocks, opening the door to numerous different functionalities and potential applications. As a consequence, a large number of building blocks that can act as light-harvesters, semiconductors, ligands, binding sites or redox centers have recently been integrated into the scaffolds of COFs. This unique combination of reticular chemistry with the molecular control of intrinsic properties paves the way towards the design of new semiconducting materials for (opto-)electronic applications such as sensors, photocatalysts or -electrodes, supercapacitor and battery materials, solar-harvesting devices or light emitting diodes. With new developments regarding the linkage motif, highly stable but still tunable COFs have been developed for applications even under harsh conditions. Further, the molecular stacking modes and distances in the COFs have been investigated as a powerful means to control optical and electrical characteristics of these self-assembled frameworks. Advanced understanding of optoelectronic processes in COFs has enabled their implementation in optoelectronic devices with promising potential for real-world applications. This review highlights the key developments of design concepts for the synthesis of electro- and photoactive COFs as well as our understanding of optoelectronic processes in these frameworks, hence establishing a new paradigm for the rational construction of well-defined novel optoelectronic materials and devices.}, keywords = {Molecularly-Functionalized}, pubstate = {published}, tppubtype = {article} } Covalent organic frameworks (COFs) are crystalline porous materials constructed from molecular building blocks using diverse linkage chemistries. Their modular construction system allows not only for tailor-made design but also for an immense variety of building blocks, opening the door to numerous different functionalities and potential applications. As a consequence, a large number of building blocks that can act as light-harvesters, semiconductors, ligands, binding sites or redox centers have recently been integrated into the scaffolds of COFs. This unique combination of reticular chemistry with the molecular control of intrinsic properties paves the way towards the design of new semiconducting materials for (opto-)electronic applications such as sensors, photocatalysts or -electrodes, supercapacitor and battery materials, solar-harvesting devices or light emitting diodes. With new developments regarding the linkage motif, highly stable but still tunable COFs have been developed for applications even under harsh conditions. Further, the molecular stacking modes and distances in the COFs have been investigated as a powerful means to control optical and electrical characteristics of these self-assembled frameworks. Advanced understanding of optoelectronic processes in COFs has enabled their implementation in optoelectronic devices with promising potential for real-world applications. This review highlights the key developments of design concepts for the synthesis of electro- and photoactive COFs as well as our understanding of optoelectronic processes in these frameworks, hence establishing a new paradigm for the rational construction of well-defined novel optoelectronic materials and devices. |
| 179. | R M Kluge, N Saxena, P Müller-Buschbaum A Solution-Processable Polymer-Based Thin-Film Thermoelectric Generator Journal Article Advanced Energy and Sustainability Research, 2 (1), pp. 2000060, 2020, ISSN: 2699-9412. Abstract | Links | Tags: Foundry Organic, Solid-Solid @article{, title = {A Solution-Processable Polymer-Based Thin-Film Thermoelectric Generator}, author = {R M Kluge and N Saxena and P M\"{u}ller-Buschbaum}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/aesr.202000060}, doi = {https://doi.org/10.1002/aesr.202000060}, issn = {2699-9412}, year = {2020}, date = {2020-12-15}, journal = {Advanced Energy and Sustainability Research}, volume = {2}, number = {1}, pages = {2000060}, abstract = {Thermoelectric modules are capable of transforming thermal energy into electrical power. Implementing earth-abundant and cost-effective organic materials, they can contribute to an eco-friendly way of energy production out of low-grade waste heat and natural heat sources via the Seebeck effect. Moreover, the flexibility of organic materials can allow for adaption to curved surfaces such as the human skin and wearable electronics. Herein, a solution-processable thermoelectric generator (TEG) using exclusively polymers as active materials is presented. The high-mobility n-type polymer poly[[N,N-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5-(2,2-bithiophene)] (P(NDI2OD-T2)) and the widely studied p-type polymer blend poly(3,4-ethylene-dioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) are combined into a thin-film TEG. The presented device design is not limited to this system but is applicable to any pair of organic materials processable from solution and can be easily upscaled to fully flexible devices via, e.g., printing and roll-to-roll processing.}, keywords = {Foundry Organic, Solid-Solid}, pubstate = {published}, tppubtype = {article} } Thermoelectric modules are capable of transforming thermal energy into electrical power. Implementing earth-abundant and cost-effective organic materials, they can contribute to an eco-friendly way of energy production out of low-grade waste heat and natural heat sources via the Seebeck effect. Moreover, the flexibility of organic materials can allow for adaption to curved surfaces such as the human skin and wearable electronics. Herein, a solution-processable thermoelectric generator (TEG) using exclusively polymers as active materials is presented. The high-mobility n-type polymer poly[[N,N-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5-(2,2-bithiophene)] (P(NDI2OD-T2)) and the widely studied p-type polymer blend poly(3,4-ethylene-dioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) are combined into a thin-film TEG. The presented device design is not limited to this system but is applicable to any pair of organic materials processable from solution and can be easily upscaled to fully flexible devices via, e.g., printing and roll-to-roll processing. |
| 178. | J B Lee, H Walker, Y Li, T W Nam, A Rakovich, R Sapienza, Y S Jung, Y S Nam, S A Maier, E Cortés Template Dissolution Interfacial Patterning of Single Colloids for Nanoelectrochemistry and Nanosensing Journal Article ACS Nano, 2020, ISSN: 1936-0851. Abstract | Links | Tags: Foundry Inorganic @article{, title = {Template Dissolution Interfacial Patterning of Single Colloids for Nanoelectrochemistry and Nanosensing}, author = {J B Lee and H Walker and Y Li and T W Nam and A Rakovich and R Sapienza and Y S Jung and Y S Nam and S A Maier and E Cort\'{e}s}, url = {https://doi.org/10.1021/acsnano.0c09319}, doi = {10.1021/acsnano.0c09319}, issn = {1936-0851}, year = {2020}, date = {2020-12-03}, journal = {ACS Nano}, abstract = {Deterministic positioning and assembly of colloidal nanoparticles (NPs) onto substrates is a core requirement and a promising alternative to top-down lithography to create functional nanostructures and nanodevices with intriguing optical, electrical, and catalytic features. Capillary-assisted particle assembly (CAPA) has emerged as an attractive technique to this end, as it allows controlled and selective assembly of a wide variety of NPs onto predefined topographical templates using capillary forces. One critical issue with CAPA, however, lies in its final printing step, where high printing yields are possible only with the use of an adhesive polymer film. To address this problem, we have developed a template dissolution interfacial patterning (TDIP) technique to assemble and print single colloidal AuNP arrays onto various dielectric and conductive substrates in the absence of any adhesion layer, with printing yields higher than 98%. The TDIP approach grants direct access to the interface between the AuNP and the target surface, enabling the use of colloidal AuNPs as building blocks for practical applications. The versatile applicability of TDIP is demonstrated by the creation of direct electrical junctions for electro- and photoelectrochemistry and nanoparticle-on-mirror geometries for single-particle molecular sensing.}, keywords = {Foundry Inorganic}, pubstate = {published}, tppubtype = {article} } Deterministic positioning and assembly of colloidal nanoparticles (NPs) onto substrates is a core requirement and a promising alternative to top-down lithography to create functional nanostructures and nanodevices with intriguing optical, electrical, and catalytic features. Capillary-assisted particle assembly (CAPA) has emerged as an attractive technique to this end, as it allows controlled and selective assembly of a wide variety of NPs onto predefined topographical templates using capillary forces. One critical issue with CAPA, however, lies in its final printing step, where high printing yields are possible only with the use of an adhesive polymer film. To address this problem, we have developed a template dissolution interfacial patterning (TDIP) technique to assemble and print single colloidal AuNP arrays onto various dielectric and conductive substrates in the absence of any adhesion layer, with printing yields higher than 98%. The TDIP approach grants direct access to the interface between the AuNP and the target surface, enabling the use of colloidal AuNPs as building blocks for practical applications. The versatile applicability of TDIP is demonstrated by the creation of direct electrical junctions for electro- and photoelectrochemistry and nanoparticle-on-mirror geometries for single-particle molecular sensing. |
| 177. | L Wolz, C Heshmatpour, A Perri, D Polli, G Cerullo, J J Finley, E Thyrhaug, J Hauer, A V Stier Time-domain photocurrent spectroscopy based on a common-path birefringent interferometer Journal Article Review of Scientific Instruments, 91 (12), pp. 123101, 2020. Links | Tags: Foundry Inorganic @article{, title = {Time-domain photocurrent spectroscopy based on a common-path birefringent interferometer}, author = {L Wolz and C Heshmatpour and A Perri and D Polli and G Cerullo and J J Finley and E Thyrhaug and J Hauer and A V Stier}, url = {https://aip.scitation.org/doi/abs/10.1063/5.0023543}, doi = {10.1063/5.0023543}, year = {2020}, date = {2020-12-02}, journal = {Review of Scientific Instruments}, volume = {91}, number = {12}, pages = {123101}, keywords = {Foundry Inorganic}, pubstate = {published}, tppubtype = {article} } |
| 176. | T M Brenner, C Gehrmann, R Korobko, T Livneh, D A Egger, O Yaffe Anharmonic host-lattice dynamics enable fast ion conduction in superionic AgI Journal Article Physical Review Materials, 4 (11), pp. 115402, 2020. Links | Tags: Solid-Solid @article{, title = {Anharmonic host-lattice dynamics enable fast ion conduction in superionic AgI}, author = {T M Brenner and C Gehrmann and R Korobko and T Livneh and D A Egger and O Yaffe}, url = {https://link.aps.org/doi/10.1103/PhysRevMaterials.4.115402}, doi = {10.1103/PhysRevMaterials.4.115402}, year = {2020}, date = {2020-11-30}, journal = {Physical Review Materials}, volume = {4}, number = {11}, pages = {115402}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } |
| 175. | M T Sirtl, M Armer, L K Reb, R Hooijer, P Dörflinger, M A Scheel, K Tvingstedt, P Rieder, N Glück, P Pandit, S V Roth, P Müller-Buschbaum, V Dyakonov, T Bein Optoelectronic Properties of Cs2AgBiBr6 Thin Films: The Influence of Precursor Stoichiometry Journal Article ACS Applied Energy Materials, 2020. Abstract | Links | Tags: Foundry Inorganic, Solid-Solid @article{, title = {Optoelectronic Properties of Cs2AgBiBr6 Thin Films: The Influence of Precursor Stoichiometry}, author = {M T Sirtl and M Armer and L K Reb and R Hooijer and P D\"{o}rflinger and M A Scheel and K Tvingstedt and P Rieder and N Gl\"{u}ck and P Pandit and S V Roth and P M\"{u}ller-Buschbaum and V Dyakonov and T Bein}, url = {https://doi.org/10.1021/acsaem.0c01308}, doi = {10.1021/acsaem.0c01308}, year = {2020}, date = {2020-11-25}, journal = {ACS Applied Energy Materials}, abstract = {Lead-free double perovskites have recently attracted growing attention as possible alternatives to lead-based halide perovskites in photovoltaics and other optoelectronic applications. The most prominent compound Cs2AgBiBr6, however, presents issues such as a rather large and indirect band gap, high exciton binding energies, and poor charge carrier transport, especially in thin films. In order to address some of these challenges, we systematically modified the stoichiometry of the precursors used for the synthesis of thin films toward a BiBr3-deficient system. In combination with a stoichiometric excess of AgBr, we obtained highly oriented double perovskite thin films. These modifications directly boost the lifetime of the charge carriers up to 500 ns as observed by time-resolved photoluminescence spectroscopy. Moreover, time-resolved microwave conductivity studies revealed an increase of the charge carrier mobility from 3.5 to around ∼5 cm2/(V s). Solar cells comprising the modified films as planar active layers reached power conversion efficiency (PCE) values up to 1.11%, exceeding the stoichiometric reference film (∼0.97%), both on average and with champion cells. The results in this work underline the importance of controlling the nanomorphology of the bulk film. We anticipate that control of precursor stoichiometry will also offer a promising approach for enhancing the efficiency of other perovskite photovoltaic absorber materials and thin films.}, keywords = {Foundry Inorganic, Solid-Solid}, pubstate = {published}, tppubtype = {article} } Lead-free double perovskites have recently attracted growing attention as possible alternatives to lead-based halide perovskites in photovoltaics and other optoelectronic applications. The most prominent compound Cs2AgBiBr6, however, presents issues such as a rather large and indirect band gap, high exciton binding energies, and poor charge carrier transport, especially in thin films. In order to address some of these challenges, we systematically modified the stoichiometry of the precursors used for the synthesis of thin films toward a BiBr3-deficient system. In combination with a stoichiometric excess of AgBr, we obtained highly oriented double perovskite thin films. These modifications directly boost the lifetime of the charge carriers up to 500 ns as observed by time-resolved photoluminescence spectroscopy. Moreover, time-resolved microwave conductivity studies revealed an increase of the charge carrier mobility from 3.5 to around ∼5 cm2/(V s). Solar cells comprising the modified films as planar active layers reached power conversion efficiency (PCE) values up to 1.11%, exceeding the stoichiometric reference film (∼0.97%), both on average and with champion cells. The results in this work underline the importance of controlling the nanomorphology of the bulk film. We anticipate that control of precursor stoichiometry will also offer a promising approach for enhancing the efficiency of other perovskite photovoltaic absorber materials and thin films. |
| 174. | J M Scheckenbach, P Tinnefeld, V Glembockyte, T Schubert, C Forthmann Self-Regeneration and Self-Healing in DNA Origami Nanostructures Journal Article Angewandte Chemie International Edition, n/a (n/a), 2020, ISSN: 1433-7851. Abstract | Links | Tags: Foundry Organic @article{, title = {Self-Regeneration and Self-Healing in DNA Origami Nanostructures}, author = {J M Scheckenbach and P Tinnefeld and V Glembockyte and T Schubert and C Forthmann}, url = {https://doi.org/10.1002/anie.202012986}, doi = {https://doi.org/10.1002/anie.202012986}, issn = {1433-7851}, year = {2020}, date = {2020-11-23}, journal = {Angewandte Chemie International Edition}, volume = {n/a}, number = {n/a}, abstract = {DNA nanotechnology and advances in the DNA origami technique have enabled facile design and synthesis of complex and functional nanostructures. Molecular devices are, however, prone to rapid functional and structural degradation due to the high proportion of surface atoms at the nanoscale and due to complex working environments. Besides stabilizing mechanisms, approach for the self-repair of functional molecular devices are desirable. Here we exploit the self-assembly and reconfigurability of DNA origami nanostructures to induce the self-repair of defects of photoinduced and enzymatic damage. With different examples of repair in DNA nanostructures, we distinguish between unspecific self-regeneration and damage specific self-healing mechanisms. Using DNA origami nanorulers studied by atomic force and superresolution DNA PAINT microscopy, quantitative preservation of fluorescence properties is demonstrated with direct potential for improving nanoscale calibration samples.}, keywords = {Foundry Organic}, pubstate = {published}, tppubtype = {article} } DNA nanotechnology and advances in the DNA origami technique have enabled facile design and synthesis of complex and functional nanostructures. Molecular devices are, however, prone to rapid functional and structural degradation due to the high proportion of surface atoms at the nanoscale and due to complex working environments. Besides stabilizing mechanisms, approach for the self-repair of functional molecular devices are desirable. Here we exploit the self-assembly and reconfigurability of DNA origami nanostructures to induce the self-repair of defects of photoinduced and enzymatic damage. With different examples of repair in DNA nanostructures, we distinguish between unspecific self-regeneration and damage specific self-healing mechanisms. Using DNA origami nanorulers studied by atomic force and superresolution DNA PAINT microscopy, quantitative preservation of fluorescence properties is demonstrated with direct potential for improving nanoscale calibration samples. |
| 173. | S Lee, H Hwang, W Lee, D Schebarchov, Y Wy, J Grand, B Auguié, D H Wi, E Cortés, S W Han Core–Shell Bimetallic Nanoparticle Trimers for Efficient Light-to-Chemical Energy Conversion Journal Article ACS Energy Letters, pp. 3881-3890, 2020. Abstract | Links | Tags: Foundry Inorganic @article{, title = {Core\textendashShell Bimetallic Nanoparticle Trimers for Efficient Light-to-Chemical Energy Conversion}, author = {S Lee and H Hwang and W Lee and D Schebarchov and Y Wy and J Grand and B Augui\'{e} and D H Wi and E Cort\'{e}s and S W Han}, url = {https://doi.org/10.1021/acsenergylett.0c02110}, doi = {10.1021/acsenergylett.0c02110}, year = {2020}, date = {2020-11-19}, journal = {ACS Energy Letters}, pages = {3881-3890}, abstract = {Incorporation of catalytically active materials into plasmonic metal nanostructures can efficiently merge the reactivity and energy-harvesting abilities of both types of materials for visible light photocatalysis. Herein, we explore the influence of electromagnetic hotspots in the ability of plasmonic core\textendashshell colloidal structures to induce chemical transformations. For this study, we developed a synthetic strategy for the fabrication of Au nanoparticle (NP) trimers in aqueous solution through fine controlled galvanic replacement between Ag nanoprisms and Au precursors. Core\textendashshell Au@M NP trimers with catalytically active metals (M = Pd, Pt) were subsequently synthesized using Au NP trimers as templates. Our experimental and computational results highlight the synergy of geometry and composition in plasmonic catalysts for plasmon-driven chemical reactions.}, keywords = {Foundry Inorganic}, pubstate = {published}, tppubtype = {article} } Incorporation of catalytically active materials into plasmonic metal nanostructures can efficiently merge the reactivity and energy-harvesting abilities of both types of materials for visible light photocatalysis. Herein, we explore the influence of electromagnetic hotspots in the ability of plasmonic core–shell colloidal structures to induce chemical transformations. For this study, we developed a synthetic strategy for the fabrication of Au nanoparticle (NP) trimers in aqueous solution through fine controlled galvanic replacement between Ag nanoprisms and Au precursors. Core–shell Au@M NP trimers with catalytically active metals (M = Pd, Pt) were subsequently synthesized using Au NP trimers as templates. Our experimental and computational results highlight the synergy of geometry and composition in plasmonic catalysts for plasmon-driven chemical reactions. |
| 172. | S Subramanian, Q T Campbell, S K Moser, J Kiemle, P Zimmermann, P Seifert, F Sigger, D Sharma, H Al-Sadeg, M Labella, D Waters, R M Feenstra, R J Koch, C Jozwiak, A Bostwick, E Rotenberg, I Dabo, A W Holleitner, T E Beechem, U Wurstbauer, J A Robinson Photophysics and Electronic Structure of Lateral Graphene/MoS2 and Metal/MoS2 Junctions Journal Article ACS Nano, 2020, ISSN: 1936-0851. Abstract | Links | Tags: Solid-Solid @article{, title = {Photophysics and Electronic Structure of Lateral Graphene/MoS2 and Metal/MoS2 Junctions}, author = {S Subramanian and Q T Campbell and S K Moser and J Kiemle and P Zimmermann and P Seifert and F Sigger and D Sharma and H Al-Sadeg and M Labella and D Waters and R M Feenstra and R J Koch and C Jozwiak and A Bostwick and E Rotenberg and I Dabo and A W Holleitner and T E Beechem and U Wurstbauer and J A Robinson}, url = {https://doi.org/10.1021/acsnano.0c02527}, doi = {10.1021/acsnano.0c02527}, issn = {1936-0851}, year = {2020}, date = {2020-11-16}, journal = {ACS Nano}, abstract = {Integration of semiconducting transition metal dichalcogenides (TMDs) into functional optoelectronic circuitries requires an understanding of the charge transfer across the interface between the TMD and the contacting material. Here, we use spatially resolved photocurrent microscopy to demonstrate electronic uniformity at the epitaxial graphene/molybdenum disulfide (EG/MoS2) interface. A 10× larger photocurrent is extracted at the EG/MoS2 interface when compared to the metal (Ti/Au)/MoS2 interface. This is supported by semi-local density functional theory (DFT), which predicts the Schottky barrier at the EG/MoS2 interface to be ∼2× lower than that at Ti/MoS2. We provide a direct visualization of a 2D material Schottky barrier through combination of angle-resolved photoemission spectroscopy with spatial resolution selected to be ∼300 nm (nano-ARPES) and DFT calculations. A bending of ∼500 meV over a length scale of ∼2\textendash3 μm in the valence band maximum of MoS2 is observed via nano-ARPES. We explicate a correlation between experimental demonstration and theoretical predictions of barriers at graphene/TMD interfaces. Spatially resolved photocurrent mapping allows for directly visualizing the uniformity of built-in electric fields at heterostructure interfaces, providing a guide for microscopic engineering of charge transport across heterointerfaces. This simple probe-based technique also speaks directly to the 2D synthesis community to elucidate electronic uniformity at domain boundaries alongside morphological uniformity over large areas.}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } Integration of semiconducting transition metal dichalcogenides (TMDs) into functional optoelectronic circuitries requires an understanding of the charge transfer across the interface between the TMD and the contacting material. Here, we use spatially resolved photocurrent microscopy to demonstrate electronic uniformity at the epitaxial graphene/molybdenum disulfide (EG/MoS2) interface. A 10× larger photocurrent is extracted at the EG/MoS2 interface when compared to the metal (Ti/Au)/MoS2 interface. This is supported by semi-local density functional theory (DFT), which predicts the Schottky barrier at the EG/MoS2 interface to be ∼2× lower than that at Ti/MoS2. We provide a direct visualization of a 2D material Schottky barrier through combination of angle-resolved photoemission spectroscopy with spatial resolution selected to be ∼300 nm (nano-ARPES) and DFT calculations. A bending of ∼500 meV over a length scale of ∼2–3 μm in the valence band maximum of MoS2 is observed via nano-ARPES. We explicate a correlation between experimental demonstration and theoretical predictions of barriers at graphene/TMD interfaces. Spatially resolved photocurrent mapping allows for directly visualizing the uniformity of built-in electric fields at heterostructure interfaces, providing a guide for microscopic engineering of charge transport across heterointerfaces. This simple probe-based technique also speaks directly to the 2D synthesis community to elucidate electronic uniformity at domain boundaries alongside morphological uniformity over large areas. |
| 171. | D B Trivedi, G Turgut, Y Qin, M Y Sayyad, D Hajra, M Howell, L Liu, S Yang, N H Patoary, H Li, M M Petrić, M Meyer, M Kremser, M Barbone, G Soavi, A V Stier, K Müller, S Yang, I S Esqueda, H Zhuang, J J Finley, S Tongay Room-Temperature Synthesis of 2D Janus Crystals and their Heterostructures Journal Article Advanced Materials, 32 (50), pp. 2006320, 2020, ISSN: 0935-9648. Abstract | Links | Tags: Foundry Inorganic, Solid-Solid @article{, title = {Room-Temperature Synthesis of 2D Janus Crystals and their Heterostructures}, author = {D B Trivedi and G Turgut and Y Qin and M Y Sayyad and D Hajra and M Howell and L Liu and S Yang and N H Patoary and H Li and M M Petri\'{c} and M Meyer and M Kremser and M Barbone and G Soavi and A V Stier and K M\"{u}ller and S Yang and I S Esqueda and H Zhuang and J J Finley and S Tongay}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.202006320}, doi = {https://doi.org/10.1002/adma.202006320}, issn = {0935-9648}, year = {2020}, date = {2020-11-11}, journal = {Advanced Materials}, volume = {32}, number = {50}, pages = {2006320}, abstract = {Abstract Janus crystals represent an exciting class of 2D materials with different atomic species on their upper and lower facets. Theories have predicted that this symmetry breaking induces an electric field and leads to a wealth of novel properties, such as large Rashba spin\textendashorbit coupling and formation of strongly correlated electronic states. Monolayer MoSSe Janus crystals have been synthesized by two methods, via controlled sulfurization of monolayer MoSe2 and via plasma stripping followed thermal annealing of MoS2. However, the high processing temperatures prevent growth of other Janus materials and their heterostructures. Here, a room-temperature technique for the synthesis of a variety of Janus monolayers with high structural and optical quality is reported. This process involves low-energy reactive radical precursors, which enables selective removal and replacement of the uppermost chalcogen layer, thus transforming classical transition metal dichalcogenides into a Janus structure. The resulting materials show clear mixed character for their excitonic transitions, and more importantly, the presented room-temperature method enables the demonstration of first vertical and lateral heterojunctions of 2D Janus TMDs. The results present significant and pioneering advances in the synthesis of new classes of 2D materials, and pave the way for the creation of heterostructures from 2D Janus layers.}, keywords = {Foundry Inorganic, Solid-Solid}, pubstate = {published}, tppubtype = {article} } Abstract Janus crystals represent an exciting class of 2D materials with different atomic species on their upper and lower facets. Theories have predicted that this symmetry breaking induces an electric field and leads to a wealth of novel properties, such as large Rashba spin–orbit coupling and formation of strongly correlated electronic states. Monolayer MoSSe Janus crystals have been synthesized by two methods, via controlled sulfurization of monolayer MoSe2 and via plasma stripping followed thermal annealing of MoS2. However, the high processing temperatures prevent growth of other Janus materials and their heterostructures. Here, a room-temperature technique for the synthesis of a variety of Janus monolayers with high structural and optical quality is reported. This process involves low-energy reactive radical precursors, which enables selective removal and replacement of the uppermost chalcogen layer, thus transforming classical transition metal dichalcogenides into a Janus structure. The resulting materials show clear mixed character for their excitonic transitions, and more importantly, the presented room-temperature method enables the demonstration of first vertical and lateral heterojunctions of 2D Janus TMDs. The results present significant and pioneering advances in the synthesis of new classes of 2D materials, and pave the way for the creation of heterostructures from 2D Janus layers. |
| 170. | F Haase, B V Lotsch Solving the COF trilemma: towards crystalline, stable and functional covalent organic frameworks Journal Article Chemical Society Reviews, 2020, ISSN: 0306-0012. Abstract | Links | Tags: Foundry Organic @article{, title = {Solving the COF trilemma: towards crystalline, stable and functional covalent organic frameworks}, author = {F Haase and B V Lotsch}, url = {http://dx.doi.org/10.1039/D0CS01027H}, doi = {10.1039/D0CS01027H}, issn = {0306-0012}, year = {2020}, date = {2020-11-06}, journal = {Chemical Society Reviews}, abstract = {Covalent organic frameworks (COFs) have entered the stage as a new generation of porous polymers which stand out by virtue of their crystallinity, diverse framework topologies and accessible pore systems. An important \textendash but still underdeveloped \textendash feature of COFs is their potentially superior stability in comparison to other porous materials. Achieving COFs which are simultaneously crystalline, stable, and functional is still challenging as reversible bond formation is one of the prime prerequisites for the crystallization of COFs. However, as the COF field matures new strategies have surfaced that bypass this crystallinity \textendash stability dichotomy. Three major approaches for obtaining both stable and crystalline COFs have taken form in recent years: Tweaking the reaction conditions for reversible linkages, separating the order inducing step and the stability inducing step, and controlling the structural degrees of freedom during assembly and in the final COF. This review discusses rational approaches to stability and crystallinity engineering in COFs, which are apt at overcoming current challenges in COF design and open up new avenues to new real-world applications of COFs.}, keywords = {Foundry Organic}, pubstate = {published}, tppubtype = {article} } Covalent organic frameworks (COFs) have entered the stage as a new generation of porous polymers which stand out by virtue of their crystallinity, diverse framework topologies and accessible pore systems. An important – but still underdeveloped – feature of COFs is their potentially superior stability in comparison to other porous materials. Achieving COFs which are simultaneously crystalline, stable, and functional is still challenging as reversible bond formation is one of the prime prerequisites for the crystallization of COFs. However, as the COF field matures new strategies have surfaced that bypass this crystallinity – stability dichotomy. Three major approaches for obtaining both stable and crystalline COFs have taken form in recent years: Tweaking the reaction conditions for reversible linkages, separating the order inducing step and the stability inducing step, and controlling the structural degrees of freedom during assembly and in the final COF. This review discusses rational approaches to stability and crystallinity engineering in COFs, which are apt at overcoming current challenges in COF design and open up new avenues to new real-world applications of COFs. |
Publications2021-02-15T13:59:22+01:00
| 219. | Increasing Photostability of Inverted Nonfullerene Organic Solar Cells by Using Fullerene Derivative Additives Journal Article ACS Applied Materials & Interfaces, 2021, ISSN: 1944-8244. |
| 218. | Graphene-on-Glass Preparation and Cleaning Methods Characterized by Single-Molecule DNA Origami Fluorescent Probes and Raman Spectroscopy Journal Article ACS Nano, 2021, ISSN: 1936-0851. |
| 217. | True Nature of the Transition-Metal Carbide/Liquid Interface Determines Its Reactivity Journal Article ACS Catalysis, pp. 4920-4928, 2021. |
| 216. | Bright single photon emitters with enhanced quantum efficiency in a two-dimensional semiconductor coupled with dielectric nano-antennas Journal Article arXiv preprint arXiv:2103.16986, 2021. |
| 215. | In-situ Detection of Active Sites for Carbon-Based Bifunctional Oxygen Reduction and Evolution Catalysis Journal Article Electrochimica Acta, pp. 138285, 2021, ISSN: 0013-4686. |
| 214. | Paired Ru‒O‒Mo ensemble for efficient and stable alkaline hydrogen evolution reaction Journal Article Nano Energy, 82 , pp. 105767, 2021, ISSN: 2211-2855. |
| 213. | Cluster Catalysis with Lattice Oxygen: Tracing Oxygen Transport from a Magnetite (001) Support onto Small Pt Clusters Journal Article arXiv preprint arXiv:2103.16413, 2021. |
| 212. | An electrically conducting three-dimensional iron-catecholate porous framework Journal Article Angewandte Chemie International Edition, n/a (n/a), 2021, ISSN: 1433-7851. |
| 211. | Single-molecule mechanics of synthetic aromatic amide helices: Ultrafast and robust non-dissipative winding Journal Article Chem, 2021, ISSN: 2451-9294. |
| 210. | Monitoring Active Sites for Hydrogen Evolution Reaction at Model Carbon Surfaces Journal Article Physical Chemistry Chemical Physics, 2021, ISSN: 1463-9076. |
| 209. | Fast-Switching Vis–IR Electrochromic Covalent Organic Frameworks Journal Article Journal of the American Chemical Society, 2021, ISSN: 0002-7863. |
| 208. | Investigation of degradation mechanisms in PEM fuel cells caused by low-temperature cycles Journal Article International Journal of Hydrogen Energy, 2021, ISSN: 0360-3199. |
| 207. | Determining the In-Plane Orientation and Binding Mode of Single Fluorescent Dyes in DNA Origami Structures Journal Article ACS Nano, 2021, ISSN: 1936-0851. |
| 206. | The Potential of Zero Charge and the Electrochemical Interface Structure of Cu(111) in Alkaline Solutions Journal Article The Journal of Physical Chemistry C, 2021, ISSN: 1932-7447. |
| 205. | Picosecond time-resolved photon antibunching measures nanoscale exciton motion and the true number of chromophores Journal Article Nature Communications, 12 (1), pp. 1327, 2021, ISSN: 2041-1723. |
| 204. | Super-resolution Imaging of Energy Transfer by Intensity-Based STED-FRET Journal Article Nano Letters, 2021, ISSN: 1530-6984. |
| 203. | Highly Efficient Resolution-of-Identity Density Functional Theory Calculations on Central and Graphics Processing Units Journal Article Journal of Chemical Theory and Computation, 2021, ISSN: 1549-9618. |
| 202. | Activation of 2-Cyclohexenone by BF3 Coordination: Mechanistic Insights from Theory and Experiment Journal Article Angewandte Chemie International Edition, n/a (n/a), 2021, ISSN: 1433-7851. |
| 201. | Advanced Energy Materials, 11 (6), pp. 2170028, 2021, ISSN: 1614-6832. |
| 200. | Addressable nanoantennas with cleared hotspots for single-molecule detection on a portable smartphone microscope Journal Article Nature Communications, 12 (1), pp. 950, 2021, ISSN: 2041-1723. |
| 199. | Perovskite Nanocrystals: Synthesis, Stability, and Optoelectronic Applications Journal Article Small Structures, n/a (n/a), pp. 2000124, 2021, ISSN: 2688-4062. |
| 198. | Aluminum Oxide at the Monolayer Limit via Oxidant-free Plasma-Assisted Atomic Layer Deposition on GaN Journal Article arXiv preprint arXiv:2102.03642, 2021. |
| 197. | Properties of the Space Charge Layers Formed in Li-Ion Conducting Glass Ceramics Journal Article ACS Applied Materials & Interfaces, 13 (4), pp. 5853-5860, 2021, ISSN: 1944-8244. |
| 196. | Electronic properties of semiconducting Zn(Si, Ge, Sn)N2 alloys Journal Article Physical Review Materials, 5 (2), pp. 024601, 2021. |
| 195. | Examination of possible high-pressure candidates of SnTiO3: The search for novel ferroelectric materials Journal Article APL Materials, 9 (2), pp. 021103, 2021. |
| 194. | Formation Mechanisms for Phosphorene and SnIP Journal Article Angewandte Chemie International Edition, n/a (n/a), 2021, ISSN: 1433-7851. |
| 193. | Identification of Potential Optoelectronic Applications for Metal Thiophosphates Journal Article ACS Applied Materials & Interfaces, 13 (3), pp. 3836-3844, 2021, ISSN: 1944-8244. |
| 192. | Gate-Switchable Arrays of Quantum Light Emitters in Contacted Monolayer MoS2 van der Waals Heterodevices Journal Article Nano Letters, 21 (2), pp. 1040-1046, 2021, ISSN: 1530-6984. |
| 191. | Engineering the Luminescence and Generation of Individual Defect Emitters in Atomically Thin MoS2 Journal Article ACS Photonics, 2021. |
| 190. | ACS Applied Materials & Interfaces, 13 (2), pp. 2961-2970, 2021, ISSN: 1944-8244. |
| 189. | 3D Deep Learning Enables Accurate Layer Mapping of 2D Materials Journal Article ACS Nano, 15 (2), pp. 3139-3151, 2021, ISSN: 1936-0851. |
| 188. | Raman spectrum of Janus transition metal dichalcogenide monolayers WSSe and MoSSe Journal Article Physical Review B, 103 (3), pp. 035414, 2021. |
| 187. | Pulsed Interleaved MINFLUX Journal Article Nano Letters, 21 (1), pp. 840-846, 2021, ISSN: 1530-6984. |
| 186. | Charged Exciton Kinetics in Monolayer MoSe2 near Ferroelectric Domain Walls in Periodically Poled LiNbO3 Journal Article Nano Letters, 21 (2), pp. 959-966, 2021, ISSN: 1530-6984. |
| 185. | Ultrafast hot carrier relaxation in silicon monitored by phase-resolved transient absorption spectroscopy Journal Article arXiv preprint arXiv:2101.01439, 2021. |
| 184. | DNA origami based superconducting nanowires Journal Article AIP Advances, 11 (1), pp. 015130, 2021. |
| 183. | Surface NMR Using Quantum Sensors in Diamond Book 2021. |
| 182. | 2021. |
| 181. | Challenges in Plasmonic Catalysis Journal Article ACS Nano, 14 (12), pp. 16202-16219, 2020, ISSN: 1936-0851. |
| 180. | Optoelectronic processes in covalent organic frameworks Journal Article Chemical Society Reviews, 2020, ISSN: 0306-0012. |
| 179. | A Solution-Processable Polymer-Based Thin-Film Thermoelectric Generator Journal Article Advanced Energy and Sustainability Research, 2 (1), pp. 2000060, 2020, ISSN: 2699-9412. |
| 178. | Template Dissolution Interfacial Patterning of Single Colloids for Nanoelectrochemistry and Nanosensing Journal Article ACS Nano, 2020, ISSN: 1936-0851. |
| 177. | Time-domain photocurrent spectroscopy based on a common-path birefringent interferometer Journal Article Review of Scientific Instruments, 91 (12), pp. 123101, 2020. |
| 176. | Anharmonic host-lattice dynamics enable fast ion conduction in superionic AgI Journal Article Physical Review Materials, 4 (11), pp. 115402, 2020. |
| 175. | Optoelectronic Properties of Cs2AgBiBr6 Thin Films: The Influence of Precursor Stoichiometry Journal Article ACS Applied Energy Materials, 2020. |
| 174. | Self-Regeneration and Self-Healing in DNA Origami Nanostructures Journal Article Angewandte Chemie International Edition, n/a (n/a), 2020, ISSN: 1433-7851. |
| 173. | Core–Shell Bimetallic Nanoparticle Trimers for Efficient Light-to-Chemical Energy Conversion Journal Article ACS Energy Letters, pp. 3881-3890, 2020. |
| 172. | Photophysics and Electronic Structure of Lateral Graphene/MoS2 and Metal/MoS2 Junctions Journal Article ACS Nano, 2020, ISSN: 1936-0851. |
| 171. | Room-Temperature Synthesis of 2D Janus Crystals and their Heterostructures Journal Article Advanced Materials, 32 (50), pp. 2006320, 2020, ISSN: 0935-9648. |
| 170. | Solving the COF trilemma: towards crystalline, stable and functional covalent organic frameworks Journal Article Chemical Society Reviews, 2020, ISSN: 0306-0012. |