| 22. | Al M F Fattah, M R Amin, M Mallmann, S Kasap, W Schnick, A Moewes Electronic structure investigation of wide band gap semiconductors—Mg2PN3 and Zn2PN3: experiment and theory Journal Article Journal of Physics: Condensed Matter, 32 (40), pp. 405504, 2020, ISSN: 0953-8984 1361-648X. Abstract | Links | Tags: Foundry Inorganic, Solid-Solid @article{, title = {Electronic structure investigation of wide band gap semiconductors\textemdashMg2PN3 and Zn2PN3: experiment and theory}, author = {Al M F Fattah and M R Amin and M Mallmann and S Kasap and W Schnick and A Moewes}, url = {http://dx.doi.org/10.1088/1361-648X/ab8f8a}, doi = {10.1088/1361-648x/ab8f8a}, issn = {0953-8984 1361-648X}, year = {2020}, date = {2020-07-06}, journal = {Journal of Physics: Condensed Matter}, volume = {32}, number = {40}, pages = {405504}, abstract = {The research on nitridophosphate materials has gained significant attention in recent years due to the abundance of elements like Mg, Zn, P, and N. We present a detailed study of band gap and electronic structure of M2PN3 (M = Mg, Zn), using synchrotron-based soft x-ray spectroscopy measurements as well as density functional theory (DFT) calculations. The experimental N K-edge x-ray emission spectroscopy (XES) and x-ray absorption spectroscopy (XAS) spectra are used to estimate the band gaps, which are compared with our calculations along with the values available in literature. The band gap, which is essential for electronic device applications, is experimentally determined for the first time to be 5.3 ± 0.2 eV and 4.2 ± 0.2 eV for Mg2PN3 and Zn2PN3, respectively. The experimental band gaps agree well with our calculated band gaps of 5.4 eV for Mg2PN3 and 3.9 eV for Zn2PN3, using the modified Becke\textendashJohnson (mBJ) exchange potential. The states that contribute to the band gap are investigated with the calculated density of states especially with respect to two non-equivalent N sites in the structure. The calculations and the measurements predict that both materials have an indirect band gap. The wide band gap of M2PN3 (M = Mg, Zn) could make it promising for the application in photovoltaic cells, high power RF applications, as well as power electronic devices.}, keywords = {Foundry Inorganic, Solid-Solid}, pubstate = {published}, tppubtype = {article} } The research on nitridophosphate materials has gained significant attention in recent years due to the abundance of elements like Mg, Zn, P, and N. We present a detailed study of band gap and electronic structure of M2PN3 (M = Mg, Zn), using synchrotron-based soft x-ray spectroscopy measurements as well as density functional theory (DFT) calculations. The experimental N K-edge x-ray emission spectroscopy (XES) and x-ray absorption spectroscopy (XAS) spectra are used to estimate the band gaps, which are compared with our calculations along with the values available in literature. The band gap, which is essential for electronic device applications, is experimentally determined for the first time to be 5.3 ± 0.2 eV and 4.2 ± 0.2 eV for Mg2PN3 and Zn2PN3, respectively. The experimental band gaps agree well with our calculated band gaps of 5.4 eV for Mg2PN3 and 3.9 eV for Zn2PN3, using the modified Becke–Johnson (mBJ) exchange potential. The states that contribute to the band gap are investigated with the calculated density of states especially with respect to two non-equivalent N sites in the structure. The calculations and the measurements predict that both materials have an indirect band gap. The wide band gap of M2PN3 (M = Mg, Zn) could make it promising for the application in photovoltaic cells, high power RF applications, as well as power electronic devices. |
| 21. | S Ohno, T Bernges, J Buchheim, M Duchardt, A-K Hatz, M A Kraft, H Kwak, A L Santhosha, Z Liu, N Minafra, F Tsuji, A Sakuda, R Schlem, S Xiong, Z Zhang, P Adelhelm, H Chen, A Hayashi, Y S Jung, B V Lotsch, B Roling, N M Vargas-Barbosa, W G Zeier How Certain Are the Reported Ionic Conductivities of Thiophosphate-Based Solid Electrolytes? An Interlaboratory Study Journal Article ACS Energy Letters, 5 (3), pp. 910-915, 2020. Links | Tags: Solid-Solid @article{, title = {How Certain Are the Reported Ionic Conductivities of Thiophosphate-Based Solid Electrolytes? An Interlaboratory Study}, author = {S Ohno and T Bernges and J Buchheim and M Duchardt and A-K Hatz and M A Kraft and H Kwak and A L Santhosha and Z Liu and N Minafra and F Tsuji and A Sakuda and R Schlem and S Xiong and Z Zhang and P Adelhelm and H Chen and A Hayashi and Y S Jung and B V Lotsch and B Roling and N M Vargas-Barbosa and W G Zeier}, url = {https://doi.org/10.1021/acsenergylett.9b02764}, doi = {10.1021/acsenergylett.9b02764}, year = {2020}, date = {2020-03-13}, journal = {ACS Energy Letters}, volume = {5}, number = {3}, pages = {910-915}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } |
| 20. | S Harm, A-K Hatz, C Schneider, C Hoefer, C Hoch, B V Lotsch Finding the Right Blend: Interplay Between Structure and Sodium Ion Conductivity in the System Na5AlS4–Na4SiS4 Journal Article Frontiers in Chemistry, 8 , pp. 90, 2020, ISSN: 2296-2646. Abstract | Links | Tags: Solid-Solid @article{, title = {Finding the Right Blend: Interplay Between Structure and Sodium Ion Conductivity in the System Na5AlS4\textendashNa4SiS4}, author = {S Harm and A-K Hatz and C Schneider and C Hoefer and C Hoch and B V Lotsch}, url = {https://www.frontiersin.org/article/10.3389/fchem.2020.00090}, doi = {10.3389/fchem.2020.00090}, issn = {2296-2646}, year = {2020}, date = {2020-02-18}, journal = {Frontiers in Chemistry}, volume = {8}, pages = {90}, abstract = {The rational design of high performance sodium solid electrolytes is one of the key challenges in modern battery research. In this work, we identify new sodium ion conductors in the substitution series Na_{5-x}Al_{1-x}Si_{x}S4 (0 ≤ x ≤ 1), which are entirely based on earth-abundant elements. These compounds exhibit conductivities ranging from 1.64 · 10^{−7} for Na_{4}SiS_{4} to 2.04 · 10^{−5} for Na_{8.5}(AlS_{4})_{0.5}(SiS_{4})_{1.5} (x = 0.75). We determined the crystal structures of the Na^{+}-ion conductors Na_{4}SiS_{4} as well as hitherto unknown Na_{5}AlS_{4} and Na_{9}(AlS_{4})(SiS_{4}). Na^{+}-ion conduction pathways were calculated by bond valence energy landscape (BVEL) calculations for all new structures highlighting the influence of the local coordination symmetry of sodium ions on the energy landscape within this family. Our findings show that the interplay of charge carrier concentration and low site symmetry of sodium ions can enhance the conductivity by several orders of magnitude.}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } The rational design of high performance sodium solid electrolytes is one of the key challenges in modern battery research. In this work, we identify new sodium ion conductors in the substitution series Na5-xAl1-xSixS4 (0 ≤ x ≤ 1), which are entirely based on earth-abundant elements. These compounds exhibit conductivities ranging from 1.64 · 10−7 for Na4SiS4 to 2.04 · 10−5 for Na8.5(AlS4)0.5(SiS4)1.5 (x = 0.75). We determined the crystal structures of the Na+-ion conductors Na4SiS4 as well as hitherto unknown Na5AlS4 and Na9(AlS4)(SiS4). Na+-ion conduction pathways were calculated by bond valence energy landscape (BVEL) calculations for all new structures highlighting the influence of the local coordination symmetry of sodium ions on the energy landscape within this family. Our findings show that the interplay of charge carrier concentration and low site symmetry of sodium ions can enhance the conductivity by several orders of magnitude. |
| 19. | S S Yin, L Song, S L Xia, Y J Cheng, N Hohn, W Chen, K Wang, W Cao, S J Hou, P Muller-Buschbaum Key Factors for Template-Oriented Porous Titania Synthesis: Solvents and Catalysts Journal Article Small Methods, 2020, ISSN: 2366-9608. Links | Tags: Solid-Solid @article{, title = {Key Factors for Template-Oriented Porous Titania Synthesis: Solvents and Catalysts}, author = {S S Yin and L Song and S L Xia and Y J Cheng and N Hohn and W Chen and K Wang and W Cao and S J Hou and P Muller-Buschbaum}, url = {<Go to ISI>://WOS:000507321300001}, doi = {10.1002/smtd.201900689}, issn = {2366-9608}, year = {2020}, date = {2020-01-15}, journal = {Small Methods}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } |
| 18. | S Rieger, B J Bohn, M Doblinger, A F Richter, Y Tong, K Wang, P Muller-Buschbaum, L Polavarapu, L Leppert, J K Stolarczyk, J Feldmann Excitons and narrow bands determine the optical properties of cesium bismuth halides Journal Article Physical Review B, 100 (20), 2019, ISSN: 2469-9950. Links | Tags: Foundry Inorganic, Solid-Solid @article{, title = {Excitons and narrow bands determine the optical properties of cesium bismuth halides}, author = {S Rieger and B J Bohn and M Doblinger and A F Richter and Y Tong and K Wang and P Muller-Buschbaum and L Polavarapu and L Leppert and J K Stolarczyk and J Feldmann}, url = {<Go to ISI>://WOS:000498055800001}, doi = {10.1103/PhysRevB.100.201404}, issn = {2469-9950}, year = {2019}, date = {2019-11-20}, journal = {Physical Review B}, volume = {100}, number = {20}, keywords = {Foundry Inorganic, Solid-Solid}, pubstate = {published}, tppubtype = {article} } |
| 17. | L Janker, Y Tong, L Polavarapu, J Feldmann, A S Urban, H J Krenner Real-Time Electron and Hole Transport Dynamics in Halide Perovskite Nanowires Journal Article Nano Letters, 19 (12), pp. 8701-8707, 2019, ISSN: 1530-6984. Links | Tags: Solid-Solid @article{, title = {Real-Time Electron and Hole Transport Dynamics in Halide Perovskite Nanowires}, author = {L Janker and Y Tong and L Polavarapu and J Feldmann and A S Urban and H J Krenner}, url = {<Go to ISI>://WOS:000502687500044}, doi = {10.1021/acs.nanolett.9b03396}, issn = {1530-6984}, year = {2019}, date = {2019-10-30}, journal = {Nano Letters}, volume = {19}, number = {12}, pages = {8701-8707}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } |
| 16. | G Grinblat, I Abdelwahab, M P Nielsen, P Dichtl, K Leng, R F Oulton, K P Loh, S A Maier Ultrafast All-Optical Modulation in 2D Hybrid Perovskites Journal Article ACS Nano, 13 (8), pp. 9504-9510, 2019, ISSN: 1936-0851. Links | Tags: Solid-Solid @article{, title = {Ultrafast All-Optical Modulation in 2D Hybrid Perovskites}, author = {G Grinblat and I Abdelwahab and M P Nielsen and P Dichtl and K Leng and R F Oulton and K P Loh and S A Maier}, url = {https://doi.org/10.1021/acsnano.9b04483}, doi = {10.1021/acsnano.9b04483}, issn = {1936-0851}, year = {2019}, date = {2019-08-27}, journal = {ACS Nano}, volume = {13}, number = {8}, pages = {9504-9510}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } |
| 15. | L Polavarapu, H Huang, Y Li, Y Tong, E-P Yao, M Döblinger, M W Feil, A F Richter, A L Rogach, J Feldmann Spontaneous Crystallization of Perovskite Nanocrystals in Nonpolar Organic Solvents: A Versatile Approach for their Shape-controlled Synthesis Journal Article Angewandte Chemie International Edition, 0 (ja), 2019, ISSN: 1433-7851. Abstract | Links | Tags: Solid-Solid @article{, title = {Spontaneous Crystallization of Perovskite Nanocrystals in Nonpolar Organic Solvents: A Versatile Approach for their Shape-controlled Synthesis}, author = {L Polavarapu and H Huang and Y Li and Y Tong and E-P Yao and M D\"{o}blinger and M W Feil and A F Richter and A L Rogach and J Feldmann}, url = {https://doi.org/10.1002/anie.201906862}, doi = {10.1002/anie.201906862}, issn = {1433-7851}, year = {2019}, date = {2019-08-21}, journal = {Angewandte Chemie International Edition}, volume = {0}, number = {ja}, abstract = {The growing demand of perovskite nanocrystals (NCs) for various applications has stimulated great research interest in the development of facile synthetic methods. They have often been synthesized by either ligand assisted reprecipitation (LARP) at room temperature or by hot-injection at high temperatures and inert atmosphere. However, the use of polar solvents in LARP effects their stability. Herein, we report on the spontaneous crystallization of perovskite nanocrystals in nonpolar organic media at ambient conditions by simple mixing of precursor-ligand complexes without applying any external stimuli. The shape of the NCs can be controlled from nanocubes to nanoplatelets by varying the ratio of monovalent (e.g. formamidinium+ (FA+) and Cs+) to divalent (Pb2+) cation-ligand complexes. The precursor-ligand complexes are stable for months, and thus perovskite NCs can be readily prepared prior to use. Moreover, we show that this versatile synthetic process is scalable and can be generally applicable for perovskite NCs of different compositions.}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } The growing demand of perovskite nanocrystals (NCs) for various applications has stimulated great research interest in the development of facile synthetic methods. They have often been synthesized by either ligand assisted reprecipitation (LARP) at room temperature or by hot-injection at high temperatures and inert atmosphere. However, the use of polar solvents in LARP effects their stability. Herein, we report on the spontaneous crystallization of perovskite nanocrystals in nonpolar organic media at ambient conditions by simple mixing of precursor-ligand complexes without applying any external stimuli. The shape of the NCs can be controlled from nanocubes to nanoplatelets by varying the ratio of monovalent (e.g. formamidinium+ (FA+) and Cs+) to divalent (Pb2+) cation-ligand complexes. The precursor-ligand complexes are stable for months, and thus perovskite NCs can be readily prepared prior to use. Moreover, we show that this versatile synthetic process is scalable and can be generally applicable for perovskite NCs of different compositions. |
| 14. | S D Gennaro, Y Li, S A Maier, R F Oulton Nonlinear Pancharatnam−Berry Phase Metasurfaces beyond the Dipole Approximation Journal Article ACS Photonics, 2019. Links | Tags: Solid-Solid @article{, title = {Nonlinear Pancharatnam−Berry Phase Metasurfaces beyond the Dipole Approximation}, author = {S D Gennaro and Y Li and S A Maier and R F Oulton}, url = {https://doi.org/10.1021/acsphotonics.9b00877}, doi = {10.1021/acsphotonics.9b00877}, year = {2019}, date = {2019-08-12}, journal = {ACS Photonics}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } |
| 13. | T Wu, K Li, N Zhang, J Xia, Q Zeng, X Wen, U S Dinish, M Olivo, Z Shen, Z Liu, Q Xiong, Y Luo, S A Maier, L Wei Ultrawideband Surface Enhanced Raman Scattering in Hybrid Graphene Fragmented-Gold Substrates via Cold-Etching Journal Article Advanced Optical Materials, 0 (0), pp. 1900905, 2019, ISSN: 2195-1071. Abstract | Links | Tags: Solid-Solid @article{, title = {Ultrawideband Surface Enhanced Raman Scattering in Hybrid Graphene Fragmented-Gold Substrates via Cold-Etching}, author = {T Wu and K Li and N Zhang and J Xia and Q Zeng and X Wen and U S Dinish and M Olivo and Z Shen and Z Liu and Q Xiong and Y Luo and S A Maier and L Wei}, url = {https://doi.org/10.1002/adom.201900905}, doi = {10.1002/adom.201900905}, issn = {2195-1071}, year = {2019}, date = {2019-08-08}, journal = {Advanced Optical Materials}, volume = {0}, number = {0}, pages = {1900905}, abstract = {Abstract Conventional surface enhanced Raman scattering (SERS) substrates are well known for their supreme electromagnetic enhancements and ultrahigh sensitivity in detecting molecules at low concentrations. However, large-area quasi-uniform SERS substrates are difficult to achieve by standard top-down nanofabrication techniques, resulting in fluctuant SERS responses and unwanted fluorescence interferences, which severely limit their performances in practical applications. To tackle these challenges, a large-scale quasi-uniform hybrid graphene fragmented-gold substrate with stable and reproducible SERS readouts as well as large enhancement factors over an ultrawideband spectrum is developed. The hybrid substrate is fabricated via cold-etching through a controllable break up of a thin gold film followed by a graphene transfer. The stimulated localized surface plasmons interact strongly with the graphene layer, leading to spectrally and spatially modified graphene-mediated surface enhanced Raman scattering (GSERS) responses. The perfect monolayer graphene of the GSERS substrate prevents adsorbates from the atmosphere and direct contact between bonded molecules and gold, thus reducing the catalytic activity of gold and producing clean, stable, and reproducible molecular Raman signals. The easy-fabricated hybrid GSERS substrate not only provides a powerful platform to collect robust molecular Raman spectra but also shows great potentials for future mass production of high-performance nanophotonic devices.}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } Abstract Conventional surface enhanced Raman scattering (SERS) substrates are well known for their supreme electromagnetic enhancements and ultrahigh sensitivity in detecting molecules at low concentrations. However, large-area quasi-uniform SERS substrates are difficult to achieve by standard top-down nanofabrication techniques, resulting in fluctuant SERS responses and unwanted fluorescence interferences, which severely limit their performances in practical applications. To tackle these challenges, a large-scale quasi-uniform hybrid graphene fragmented-gold substrate with stable and reproducible SERS readouts as well as large enhancement factors over an ultrawideband spectrum is developed. The hybrid substrate is fabricated via cold-etching through a controllable break up of a thin gold film followed by a graphene transfer. The stimulated localized surface plasmons interact strongly with the graphene layer, leading to spectrally and spatially modified graphene-mediated surface enhanced Raman scattering (GSERS) responses. The perfect monolayer graphene of the GSERS substrate prevents adsorbates from the atmosphere and direct contact between bonded molecules and gold, thus reducing the catalytic activity of gold and producing clean, stable, and reproducible molecular Raman signals. The easy-fabricated hybrid GSERS substrate not only provides a powerful platform to collect robust molecular Raman spectra but also shows great potentials for future mass production of high-performance nanophotonic devices. |
| 12. | M Blauth, G Vest, S L Rosemary, M Prechtl, O Hartwig, M Jurgensen, M Kaniber, A V Stier, J J Finley Ultracompact Photodetection in Atomically Thin MoSe2 Journal Article Acs Photonics, 6 (8), pp. 1902-1909, 2019, ISSN: 2330-4022. Links | Tags: Foundry Inorganic, Solid-Solid @article{, title = {Ultracompact Photodetection in Atomically Thin MoSe2}, author = {M Blauth and G Vest and S L Rosemary and M Prechtl and O Hartwig and M Jurgensen and M Kaniber and A V Stier and J J Finley}, url = {<Go to ISI>://WOS:000482545400012}, doi = {10.1021/acsphotonics.9b00785}, issn = {2330-4022}, year = {2019}, date = {2019-07-30}, journal = {Acs Photonics}, volume = {6}, number = {8}, pages = {1902-1909}, keywords = {Foundry Inorganic, Solid-Solid}, pubstate = {published}, tppubtype = {article} } |
| 11. | V A Hintermayr, C Lampe, M Low, J Roemer, W Vanderlinden, M Gramlich, A X Bohm, C Sattler, B Nickel, T Lohmuller, A S Urban Polymer Nanoreactors Shield Perovskite Nanocrystals from Degradation Journal Article Nano Letters, 19 (8), pp. 4928-4933, 2019, ISSN: 1530-6984. Links | Tags: Foundry Inorganic, Solid-Solid @article{, title = {Polymer Nanoreactors Shield Perovskite Nanocrystals from Degradation}, author = {V A Hintermayr and C Lampe and M Low and J Roemer and W Vanderlinden and M Gramlich and A X Bohm and C Sattler and B Nickel and T Lohmuller and A S Urban}, url = {<Go to ISI>://WOS:000481563800015}, doi = {10.1021/acs.nanolett.9b00982}, issn = {1530-6984}, year = {2019}, date = {2019-07-19}, journal = {Nano Letters}, volume = {19}, number = {8}, pages = {4928-4933}, keywords = {Foundry Inorganic, Solid-Solid}, pubstate = {published}, tppubtype = {article} } |
| 10. | L V Besteiro, P Yu, Z M Wang, A W Holleitner, G V Hartland, G P Wiederrecht, A O Govorov The fast and the furious: Ultrafast hot electrons in plasmonic metastructures. Size and structure matter Journal Article Nano Today, 27 , pp. 120-145, 2019, ISSN: 1748-0132. Links | Tags: Solid-Solid @article{, title = {The fast and the furious: Ultrafast hot electrons in plasmonic metastructures. Size and structure matter}, author = {L V Besteiro and P Yu and Z M Wang and A W Holleitner and G V Hartland and G P Wiederrecht and A O Govorov}, url = {<Go to ISI>://WOS:000482526300011}, doi = {10.1016/j.nantod.2019.05.006}, issn = {1748-0132}, year = {2019}, date = {2019-07-18}, journal = {Nano Today}, volume = {27}, pages = {120-145}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } |
| 9. | A Biewald, N Giesbrecht, T Bein, P Docampo, A Hartschuh, R Ciesielski Temperature-Dependent Ambipolar Charge Carrier Mobility in Large-Crystal Hybrid Halide Perovskite Thin Films Journal Article ACS Applied Materials & Interfaces, 11 (23), pp. 20838-20844, 2019, ISSN: 1944-8244. Abstract | Links | Tags: Solid-Solid @article{, title = {Temperature-Dependent Ambipolar Charge Carrier Mobility in Large-Crystal Hybrid Halide Perovskite Thin Films}, author = {A Biewald and N Giesbrecht and T Bein and P Docampo and A Hartschuh and R Ciesielski}, url = {https://doi.org/10.1021/acsami.9b04592}, doi = {10.1021/acsami.9b04592}, issn = {1944-8244}, year = {2019}, date = {2019-06-12}, journal = {ACS Applied Materials & Interfaces}, volume = {11}, number = {23}, pages = {20838-20844}, abstract = {Perovskite-based thin-film solar cells today reach power conversion efficiencies of more than 22%. Methylammonium lead iodide (MAPI) is prototypical for this material class of hybrid halide perovskite semiconductors and at the focal point of interest for a growing community in research and engineering. Here, a detailed understanding of the charge carrier transport and its limitations by underlying scattering mechanisms is of great interest to the material’s optimization and development. In this article, we present an all-optical study of the charge carrier diffusion properties in large-crystal MAPI thin films in the tetragonal crystal phase from 170 K to room temperature. We probe the local material properties of individual crystal grains within a MAPI thin film and find a steady decrease of the charge carrier diffusion constant with increasing temperature. From the resulting charge carrier mobility, we find a power law dependence of μ ∝ Tm with m = −(1.8 ± 0.1). We further study the temperature-dependent mobility of the orthorhombic crystal phase from 50 to 140 K and observe a distinctly different exponent of m = −(1.2 ± 0.1).}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } Perovskite-based thin-film solar cells today reach power conversion efficiencies of more than 22%. Methylammonium lead iodide (MAPI) is prototypical for this material class of hybrid halide perovskite semiconductors and at the focal point of interest for a growing community in research and engineering. Here, a detailed understanding of the charge carrier transport and its limitations by underlying scattering mechanisms is of great interest to the material’s optimization and development. In this article, we present an all-optical study of the charge carrier diffusion properties in large-crystal MAPI thin films in the tetragonal crystal phase from 170 K to room temperature. We probe the local material properties of individual crystal grains within a MAPI thin film and find a steady decrease of the charge carrier diffusion constant with increasing temperature. From the resulting charge carrier mobility, we find a power law dependence of μ ∝ Tm with m = −(1.8 ± 0.1). We further study the temperature-dependent mobility of the orthorhombic crystal phase from 50 to 140 K and observe a distinctly different exponent of m = −(1.2 ± 0.1). |
| 8. | R L Z Hoye, M L Lai, M Anaya, Y Tong, K Galkowski, T Doherty, W W Li, T N Huq, S Mackowski, L Polavarapu, J Feldmann, J L Macmanus-Driscoll, R H Friend, A S Urban, S D Stranks Acs Energy Letters, 4 (5), pp. 1181-1188, 2019, ISSN: 2380-8195. Links | Tags: Solid-Solid @article{, title = {Identifying and Reducing Interfacial Losses to Enhance Color-Pure Electroluminescence in Blue-Emitting Perovskite Nanoplatelet Light-Emitting Diodes}, author = {R L Z Hoye and M L Lai and M Anaya and Y Tong and K Galkowski and T Doherty and W W Li and T N Huq and S Mackowski and L Polavarapu and J Feldmann and J L Macmanus-Driscoll and R H Friend and A S Urban and S D Stranks}, url = {<Go to ISI>://WOS:000468015600025}, doi = {10.1021/acsenergylett.9b00571}, issn = {2380-8195}, year = {2019}, date = {2019-04-17}, journal = {Acs Energy Letters}, volume = {4}, number = {5}, pages = {1181-1188}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } |
| 7. | J A Sichert, A Hemmerling, C Cardenas-Daw, A S Urban, J Feldmann Tuning the optical bandgap in layered hybrid perovskites through variation of alkyl chain length Journal Article Apl Materials, 7 (4), 2019, ISSN: 2166-532X. Links | Tags: Foundry Inorganic, Solid-Solid @article{, title = {Tuning the optical bandgap in layered hybrid perovskites through variation of alkyl chain length}, author = {J A Sichert and A Hemmerling and C Cardenas-Daw and A S Urban and J Feldmann}, url = {<Go to ISI>://WOS:000466615300017}, doi = {10.1063/1.5087296}, issn = {2166-532X}, year = {2019}, date = {2019-04-16}, journal = {Apl Materials}, volume = {7}, number = {4}, keywords = {Foundry Inorganic, Solid-Solid}, pubstate = {published}, tppubtype = {article} } |
| 6. | E Pensa, J Gargiulo, A Lauri, S Schlücker, E Cortés, S A Maier Spectral Screening of the Energy of Hot Holes over a Particle Plasmon Resonance Journal Article Nano Letters, 19 (3), pp. 1867-1874, 2019, ISSN: 1530-6984. Links | Tags: Solid-Solid @article{, title = {Spectral Screening of the Energy of Hot Holes over a Particle Plasmon Resonance}, author = {E Pensa and J Gargiulo and A Lauri and S Schl\"{u}cker and E Cort\'{e}s and S A Maier}, url = {https://doi.org/10.1021/acs.nanolett.8b04950}, doi = {10.1021/acs.nanolett.8b04950}, issn = {1530-6984}, year = {2019}, date = {2019-03-13}, journal = {Nano Letters}, volume = {19}, number = {3}, pages = {1867-1874}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } |
| 5. | B Doiron, M Mota, M P Wells, R Bower, A Mihai, Y Li, L F Cohen, N M Alford, P K Petrov, R F Oulton, S A Maier Quantifying Figures of Merit for Localized Surface Plasmon Resonance Applications: A Materials Survey Journal Article ACS Photonics, 6 (2), pp. 240-259, 2019. Links | Tags: Solid-Solid @article{, title = {Quantifying Figures of Merit for Localized Surface Plasmon Resonance Applications: A Materials Survey}, author = {B Doiron and M Mota and M P Wells and R Bower and A Mihai and Y Li and L F Cohen and N M Alford and P K Petrov and R F Oulton and S A Maier}, url = {https://doi.org/10.1021/acsphotonics.8b01369}, doi = {10.1021/acsphotonics.8b01369}, year = {2019}, date = {2019-02-20}, journal = {ACS Photonics}, volume = {6}, number = {2}, pages = {240-259}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } |
| 4. | B Miller, J Lindlau, M Bommert, A Neumann, H Yamaguchi, A W Holleitner, A Högele, U Wurstbauer Tuning the Fröhlich exciton-phonon scattering in monolayer MoS2 Journal Article Nature Communications, 10 (1), pp. 807, 2019, ISSN: 2041-1723. Abstract | Links | Tags: Solid-Solid @article{, title = {Tuning the Fr\"{o}hlich exciton-phonon scattering in monolayer MoS2}, author = {B Miller and J Lindlau and M Bommert and A Neumann and H Yamaguchi and A W Holleitner and A H\"{o}gele and U Wurstbauer}, url = {https://doi.org/10.1038/s41467-019-08764-3}, doi = {10.1038/s41467-019-08764-3}, issn = {2041-1723}, year = {2019}, date = {2019-02-18}, journal = {Nature Communications}, volume = {10}, number = {1}, pages = {807}, abstract = {Charge carriers in semiconducting transition metal dichalcogenides possess a valley degree of freedom that allows for optoelectronic applications based on the momentum of excitons. At elevated temperatures, scattering by phonons limits valley polarization, making a detailed knowledge about strength and nature of the interaction of excitons with phonons essential. In this work, we directly access exciton-phonon coupling in charge tunable single layer MoS2 devices by polarization resolved Raman spectroscopy. We observe a strong defect mediated coupling between the long-range oscillating electric field induced by the longitudinal optical phonon in the dipolar medium and the exciton. This so-called Fr\"{o}hlich exciton phonon interaction is suppressed by doping. The suppression correlates with a distinct increase of the degree of valley polarization up to 20% even at elevated temperatures of 220 K. Our result demonstrates a promising strategy to increase the degree of valley polarization towards room temperature valleytronic applications.}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } Charge carriers in semiconducting transition metal dichalcogenides possess a valley degree of freedom that allows for optoelectronic applications based on the momentum of excitons. At elevated temperatures, scattering by phonons limits valley polarization, making a detailed knowledge about strength and nature of the interaction of excitons with phonons essential. In this work, we directly access exciton-phonon coupling in charge tunable single layer MoS2 devices by polarization resolved Raman spectroscopy. We observe a strong defect mediated coupling between the long-range oscillating electric field induced by the longitudinal optical phonon in the dipolar medium and the exciton. This so-called Fröhlich exciton phonon interaction is suppressed by doping. The suppression correlates with a distinct increase of the degree of valley polarization up to 20% even at elevated temperatures of 220 K. Our result demonstrates a promising strategy to increase the degree of valley polarization towards room temperature valleytronic applications. |
| 3. | E-P Yao, B J Bohn, Y Tong, H Huang, L Polavarapu, J Feldmann Exciton Diffusion Lengths and Dissociation Rates in CsPbBr3 Nanocrystal–Fullerene Composites: Layer-by-Layer versus Blend Structures Journal Article Advanced Optical Materials, 7 (8), pp. 1801776, 2019, ISSN: 2195-1071. Abstract | Links | Tags: Solid-Solid @article{, title = {Exciton Diffusion Lengths and Dissociation Rates in CsPbBr3 Nanocrystal\textendashFullerene Composites: Layer-by-Layer versus Blend Structures}, author = {E-P Yao and B J Bohn and Y Tong and H Huang and L Polavarapu and J Feldmann}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adom.201801776}, doi = {10.1002/adom.201801776}, issn = {2195-1071}, year = {2019}, date = {2019-02-18}, journal = {Advanced Optical Materials}, volume = {7}, number = {8}, pages = {1801776}, abstract = {Abstract Solution-processable perovskite nanocrystals (NCs) are gaining increasing interest in the field of photovoltaics because of their enhanced stability compared to their thin-film counterparts. However, the charge transfer dynamics in perovskite NC based light-harvesting systems are not well understood. By applying femtosecond differential transmission (DT) spectroscopy the photoinduced charge transfer from inorganic perovskite CsPbBr3 NCs to the fullerene derivative phenyl-C61-butyric acid methyl ester (PCBM) is investigated for two fundamentally different architectures, namely layer-by-layer heterostructures and blend structures. By varying the thickness of the NC layer on top of the PCBM in the layer-by-layer heterostructure, an exciton diffusion length of 290 ± 28 nm for CsPbBr3 NC is extracted. The diffusion process is followed by an ultrafast exciton dissociation (within 200 fs) at the CsPbBr3 NC/PCBM interface. In blend structures an overall faster charge transfer process is observed. Furthermore, photoconductivity measurements on a blend structure-based photodetector reveal an effective charge extraction from the active layer resulting in a high photosensitivity. DT measurements on this blend structure including adjacent electron- or hole-transport layers give insight into the extraction process and suggest a certain degree of phase segregation, which assists the charge collection.}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } Abstract Solution-processable perovskite nanocrystals (NCs) are gaining increasing interest in the field of photovoltaics because of their enhanced stability compared to their thin-film counterparts. However, the charge transfer dynamics in perovskite NC based light-harvesting systems are not well understood. By applying femtosecond differential transmission (DT) spectroscopy the photoinduced charge transfer from inorganic perovskite CsPbBr3 NCs to the fullerene derivative phenyl-C61-butyric acid methyl ester (PCBM) is investigated for two fundamentally different architectures, namely layer-by-layer heterostructures and blend structures. By varying the thickness of the NC layer on top of the PCBM in the layer-by-layer heterostructure, an exciton diffusion length of 290 ± 28 nm for CsPbBr3 NC is extracted. The diffusion process is followed by an ultrafast exciton dissociation (within 200 fs) at the CsPbBr3 NC/PCBM interface. In blend structures an overall faster charge transfer process is observed. Furthermore, photoconductivity measurements on a blend structure-based photodetector reveal an effective charge extraction from the active layer resulting in a high photosensitivity. DT measurements on this blend structure including adjacent electron- or hole-transport layers give insight into the extraction process and suggest a certain degree of phase segregation, which assists the charge collection. |
| 2. | T Wu, Y Luo, S A Maier, L Wei Phase-matching and Peak Nonlinearity Enhanced Third-Harmonic Generation in Graphene Plasmonic Coupler Journal Article Physical Review Applied, 11 (1), pp. 014049, 2019. Abstract | Links | Tags: Solid-Solid @article{, title = {Phase-matching and Peak Nonlinearity Enhanced Third-Harmonic Generation in Graphene Plasmonic Coupler}, author = {T Wu and Y Luo and S A Maier and L Wei}, url = {https://link.aps.org/doi/10.1103/PhysRevApplied.11.014049}, doi = {10.1103/PhysRevApplied.11.014049}, year = {2019}, date = {2019-01-24}, journal = {Physical Review Applied}, volume = {11}, number = {1}, pages = {014049}, abstract = {Strong nonlinear optical effects generally require giant optical fields interacting with the nonlinear media. Doped graphene hosts electrically tunable plasmons with long lifetimes that interact strongly with light. We investigate a graphene plasmonic coupler and explore two mechanisms to pursue highly efficient third-harmonic generation (THG): (1) phase matching of graphene plasmons at fundamental- and third-harmonic frequencies and (2) peak third-order nonlinear susceptibility of doped graphene. The third-harmonic wave is mainly converted from the evanescent mode of the incident light and the THG efficiency is found to be enhanced by over 10 orders of magnitude compared with a bare monolayer graphene. The significantly enhanced nonlinear optical responses in the graphene plasmonic coupler make this configuration an ideal platform for the development of alternative frequency generators and for signal processing at midinfrared and terahertz frequencies.}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } Strong nonlinear optical effects generally require giant optical fields interacting with the nonlinear media. Doped graphene hosts electrically tunable plasmons with long lifetimes that interact strongly with light. We investigate a graphene plasmonic coupler and explore two mechanisms to pursue highly efficient third-harmonic generation (THG): (1) phase matching of graphene plasmons at fundamental- and third-harmonic frequencies and (2) peak third-order nonlinear susceptibility of doped graphene. The third-harmonic wave is mainly converted from the evanescent mode of the incident light and the THG efficiency is found to be enhanced by over 10 orders of magnitude compared with a bare monolayer graphene. The significantly enhanced nonlinear optical responses in the graphene plasmonic coupler make this configuration an ideal platform for the development of alternative frequency generators and for signal processing at midinfrared and terahertz frequencies. |
| 1. | S E J Bell, G Charron, E Cortés, J Kneipp, De La M L Chapelle, J Langer, M Procházka, V Tran, S Schlücker Towards Reliable and Quantitative Surface-Enhanced Raman Scattering (SERS): From Key Parameters to Good Analytical Practice Journal Article Angewandte Chemie International Edition, 59 (14), pp. 5454-5462, 0000, ISSN: 1433-7851. Abstract | Links | Tags: Solid-Solid @article{, title = {Towards Reliable and Quantitative Surface-Enhanced Raman Scattering (SERS): From Key Parameters to Good Analytical Practice}, author = {S E J Bell and G Charron and E Cort\'{e}s and J Kneipp and De La M L Chapelle and J Langer and M Proch\'{a}zka and V Tran and S Schl\"{u}cker}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.201908154}, doi = {10.1002/anie.201908154}, issn = {1433-7851}, journal = {Angewandte Chemie International Edition}, volume = {59}, number = {14}, pages = {5454-5462}, abstract = {Abstract Experimental results obtained in different laboratories world-wide by researchers using surface-enhanced Raman scattering (SERS) can differ significantly. We, an international team of scientists with long-standing expertise in SERS, address this issue from our perspective by presenting considerations on reliable and quantitative SERS. The central idea of this joint effort is to highlight key parameters and pitfalls that are often encountered in the literature. To that end, we provide here a series of recommendations on: a) the characterization of solid and colloidal SERS substrates by correlative electron and optical microscopy and spectroscopy, b) on the determination of the SERS enhancement factor (EF), including suitable Raman reporter/probe molecules, and finally on c) good analytical practice. We hope that both newcomers and specialists will benefit from these recommendations to increase the inter-laboratory comparability of experimental SERS results and further establish SERS as an analytical tool.}, keywords = {Solid-Solid}, pubstate = {published}, tppubtype = {article} } Abstract Experimental results obtained in different laboratories world-wide by researchers using surface-enhanced Raman scattering (SERS) can differ significantly. We, an international team of scientists with long-standing expertise in SERS, address this issue from our perspective by presenting considerations on reliable and quantitative SERS. The central idea of this joint effort is to highlight key parameters and pitfalls that are often encountered in the literature. To that end, we provide here a series of recommendations on: a) the characterization of solid and colloidal SERS substrates by correlative electron and optical microscopy and spectroscopy, b) on the determination of the SERS enhancement factor (EF), including suitable Raman reporter/probe molecules, and finally on c) good analytical practice. We hope that both newcomers and specialists will benefit from these recommendations to increase the inter-laboratory comparability of experimental SERS results and further establish SERS as an analytical tool. |
Publications2020-03-26T14:18:16+01:00