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arXiv 2020年

作者： Huang, Chun Yu Tammy Kargar, Fariborz Debnath, Topojit Debnath, Bishwajit Valentin, Michael D. Synowicki, Ron Schoeche, Stefan Lake, Roger K. Balandin, Alexander A. Center Department of Electrical and Computer Engineering and Materials Science and Engineering Program University of California RiversideCA92521 United States Department of Electrical and Computer Engineering University of California RiversideCA92521 United States Sensors and Electron Devices CCDC Army Research Laboratory AdelphiMD20783 United States J.A. Woollam Co. Inc. LincolnNE68508 United States

We report the results of Brillouin-Mandelstam spectroscopy and Mueller matrix spectroscopic ellipsometry of the nanoscale "pillar with the hat" periodic silicon structures, revealing intriguing phononic and photonic properties. It has been theoretically shown that periodic structures with properly tuned dimensions can act simultaneously as phononic and photonic crystals, strongly affecting the light-matter interactions. Acoustic phonon states can be tuned by external boundaries, either as a result of phonon confinement effects in individual nanostructures, or as a result of artificially induced external periodicity, as in the phononic crystals. The shape of the nanoscale pillar array was engineered to ensure the interplay of both effects. The Brillouin-Mandelstam spectroscopy data indicated strong flattening of the acoustic phonon dispersion in the frequency range from 2 GHz to 20 GHz and the phonon wave vector extending to the higher-order Brillouin zones. The specifics of the phonon dispersion dependence on the pillar arrays orientation suggest the presence of both periodic modulation and spatial localization effects for the acoustic phonons. The ellipsometry data reveal a distinct scatter pattern of four-fold symmetry due to nanoscale periodicity of the pillar arrays. Our results confirm the dual functionality of the nanostructured shape-engineered structure and indicate a possible new direction for fine-tuning the light-matter interaction in the next generation of photonic, optoelectronic, and phononic devices. Copyright © 2020, The Authors. All rights reserved.

关键词： Phonons

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Numerical Simulation on Effects of TCO Work Function on Performance of a-Si:H Solar Cells 4th

Numerical Simulation on Effects of TCO Work Function on Perf...

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4th International Conference on Functional materials science, ICFMS 2018

作者： Sholih, Ahmad Hamdani, Dadan Wicaksono, Sigit Tri Hidayat, Mas Irfan Purbawanto Cahyono, Yoyok Darminto Advanced Materials Research Group Department of Physics Institut Teknologi Sepuluh Nopember Kampus ITS Sukolilo Surabaya60111 Indonesia Department of Materials and Metallurgical Engineering Institut Teknologi Sepuluh Nopember Kampus ITS Sukolilo Surabaya60111 Indonesia Physics Study Program Faculty of Mathematics and Natural Science Universitas Mulawarman Samarinda Indonesia

ISBN: (纸本)9783035714968

In this paper, we have investigated the effect of the work function of transparent conducting oxides (TCO) on the performance of a-Si:H p-i-n solar cells, including open circuit voltage (VOC), short circuit current (JSC), fill factor (FF) and conversion efficiency, using AFORS-HET software. The simulation has focused on two layers: front contact work function (ΦTCO-front) and back contact work function (ΦTCO-back) with various band energy gap from 4.7 eV to 5.3 eV and 4.2 eV to 4.9 eV respectively. From the simulation results, we know that the work function of TCO greatly affects the performance of solar cells such as Voc, Jsc, FF and conversion efficiency. By optimization, we arrive at results of Voc, Jsc, FF and conversion efficiencies of 0.88 V, 8.95 mA / cm2, 65% and 5.1% respectively, by using ΦTCO-front of 5.2 eV. When ΦTCO-front > 5.2 eV, the values of VOC, FF and conversion efficiency have been saturated, while the value of the J sc actually begins to decrease. Furthermore, when the ΦTCO-back is 4.3 eV, we get the best results for VOC, Jsc, FF and conversion Efficiency of 0.9 V, 8.96 mA / cm2, 73 % and 5.9 % respectively. When ΦTCO-back > 4.3 eV, the values of VOC, FF and conversion efficiency begin to decrease, while the value of the Jsc does not change significantly. These optimizations may help for producing low cost high efficiency p-i-n solar cells experimentally. © 2019 Trans Tech Publications Ltd, Switzerland.

关键词： Work function

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Chemically Patterning Lithiophilic Interphase to Harmonize Spatial Electrons and Thermal Catalysis Dynamics for Safe Lithium Metal Batteries

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Angewandte Chemie 2025年

作者： Yisha Wang Feng Xu Edison Huixiang Ang Liu Yang Tianyang Cui Haoteng Sun Mingtong Zhang Tianxiang Yang Hanqi Zhang Jixin Zhu Yuan Hu State Key Laboratory of Fire Science University of Science and Technology of China Jin Zhai Road 96 Hefei Anhui 230026 P. R. China Frontiers Science Center for Flexible Electronics (FSCFE) Xi'an Institute of Flexible Electronics (IFE) Xi'an Institute of Biomedical Materials & Engineering Northwestern Polytechnical University (NPU) 127 West Youyi Road Xi'an 710072 P. R. China Natural Sciences and Science Education National Institute of Education Nanyang Technological University Singapore 637616 Singapore Department of Chemistry Brown University RI 02912 United States

Lithium metal batteries have garnered significant attention as promising energy storage solutions. However, their performance is often compromised by the risks associated with highly active metallic lithium, unrestricted electrode expansion, and excessive dendrites growth. Here we introduce an advanced lithiophilic anode substrate designed by chemically patterning technology for multiple security enhancements. The innovative lithiophilic array harmonizes spatial Li + to prepare compact and reversible electrodes. The composite electrodes feature an enhanced C−F component in the solid-electrolyte interface, which protects the deposited lithium metal from unwanted side reactions, thereby stabilizing electrochemical cycling. Notably, the thermal safety can be revealed through the substrate‘s excellent catalytic ability to convert smoke and toxic gases during extreme thermal runaway. This work demonstrates a novel approach to integrating battery cycling stability with thermal safety, paving the way for more reliable and secure energy storage systems.

关键词： chemically patterning lithiophilic interphase spatial electrons dynamics thermal catalysis dynamics safety lithium metal batteries

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EMPRESS. XII. Statistics on the Dynamics and Gas Mass Fraction of Extremely-Metal Poor Galaxies

arXiv

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arXiv 2023年

作者： Xu, Yi Ouchi, Masami Isobe, Yuki Nakajima, Kimihiko Ozaki, Shinobu Bouché, Nicolas F. Wise, John H. Emsellem, Eric Kusakabe, Haruka Hattori, Takashi Nagao, Tohru Chiaki, Gen Fukushima, Hajime Harikane, Yuichi Hayashi, Kohei Hirai, Yutaka Kim, Ji Hoon Maseda, Michael V. Nagamine, Kentaro Shibuya, Takatoshi Sugahara, Yuma Yajima, Hidenobu Aoyama, Shohei Fujimoto, Seiji Fukushima, Keita Hatano, Shun Inoue, Akio K. Ishigaki, Tsuyoshi Kawasaki, Masahiro Kojima, Takashi Komiyama, Yutaka Koyama, Shuhei Koyama, Yusei Lee, Chien-Hsiu Matsumoto, Akinori Mawatari, Ken Moriya, Takashi J. Motohara, Kentaro Murai, Kai Nishigaki, Moka Onodera, Masato Ono, Yoshiaki Rauch, Michael Saito, Tomoki Sasaki, Rin Suzuki, Akihiro Takeuchi, Tsutomu T. Umeda, Hiroya Umemura, Masayuki Watanabe, Kuria Yabe, Kiyoto Zhang, Yechi Institute for Cosmic Ray Research The University of Tokyo 5-1-5 Kashiwanoha Chiba Kashiwa277-8582 Japan Department of Astronomy Graduate School of Science The University of Tokyo 7-3-1 Hongo Bunkyo Tokyo113-0033 Japan National Astronomical Observatory of Japan 2-21-1 Osawa Mitaka Tokyo181-8588 Japan University of Tokyo Chiba Kashiwa277-8583 Japan Department of Physics Graduate School of Science The University of Tokyo 7-3-1 Hongo Bunkyo Tokyo113-0033 Japan Univ Lyon Univ Lyon1 ENS de Lyon CNRS Centre de Recherche Astrophysique de Lyon UMR5574 Saint-Genis-LavalF-69230 France Center for Relativistic Astrophysics School of Physics Georgia Institute of Technology AtlantaGA30332 United States European Southern Observatory Karl-Schwarzschild-Straße 2 Garching85748 Germany Observatoire de Genéve Université de Genéve 51 Ch. des Maillettes Versoix1290 Switzerland 650 North A’ohoku Place HiloHI96720 United States Research Center for Space and Cosmic Evolution Ehime University Bunkyo-cho 2-5 Ehime Matsuyama790-8577 Japan Center for Computational Sciences University of Tsukuba Ten-nodai 1-1-1 Tsukuba Ibaraki305-8577 Japan Department of Physics and Astronomy University College London Gower Street LondonWC1E 6BT United Kingdom National Institute of Technology Ichinoseki College Hagisho Ichinoseki021-8511 Japan Astronomical Institute Tohoku University 6-3 Aoba Aramaki Aoba-ku Miyagi Sendai980-8578 Japan Department of Physics and Astronomy University of Notre Dame 225 Nieuwland Science Hall Notre DameIN46556 United States Astronomy Program Department of Physics and Astronomy Seoul National University 1 Gwanak-ro Gwanak-gu Seoul08826 Korea Republic of SNU Astronomy Research Center Seoul National University 1 Gwanak-ro Gwanak-gu Seoul08826 Korea Republic of Department of Astronomy University of Wisconsin-Madison 475 N. Charter Street MadisonWI53706 United States Theoretical Astrophysics Department of Earth & Space S

We present demography of the dynamics and gas-mass fraction of 33 extremely metal-poor galaxies (EMPGs) with metallicities of 0.015 − 0.195 Zo and low stellar masses of 104 − 108 Mo in the local universe. We conduct deep optical integral-field spectroscopy (IFS) for the low-mass EMPGs with the medium high resolution (R = 7500) grism of the 8m-Subaru FOCAS IFU instrument by the EMPRESS 3D survey, and investigate Hα emission of the EMPGs. Exploiting the resolution high enough for the low-mass galaxies, we derive gas dynamics with the Hα lines by the fitting of 3-dimensional disk models. We obtain an average maximum rotation velocity (vrot) of 15 ± 3 km s−1 and an average intrinsic velocity dispersion (σ0) of 27 ± 10 km s−1 for 15 spatially resolved EMPGs out of the 33 EMPGs, and find that all of the 15 EMPGs have vrot/σ0 rot/σ0 with the decreasing stellar mass and metallicity. We derive the gas mass fraction (fgas) for all of the 33 EMPGs, and find no clear dependence on stellar mass and metallicity. These vrot/σ0 and fgas trends should be compared with young high-z galaxies observed by the forthcoming JWST IFS programs to understand the physical origins of the EMPGs in the local universe. © 2023, CC BY.

关键词： Galaxies

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iPhantom: a framework for automated creation of individualized computational phantoms and its application to CT organ dosimetry

arXiv

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arXiv 2020年

作者： Fu, Wanyi Sharma, Shobhit Abadi, Ehsan Iliopoulos, Alexandros-Stavros Wang, Qi Lo, Joseph Y. Sun, Xiaobai Segars, William P. Samei, Ehsan Department of Electrical and Computer Engineering Carl E. Ravin Advanced Imaging Laboratories Duke University DurhamNC27705 United States Department of Physics Carl E. Ravin Advanced Imaging Laboratories Duke University DurhamNC27705 United States Department of Computer Science Duke University DurhamNC27708 United States Department of Radiology Fourth Clinical Hospital of Hebei Medical University Heibei050011 China Departments of Electrical and Computer Engineering Biomedical Engineering Medical Physics Graduate Program Carl E. Ravin Advanced Imaging Laboratories Duke University DurhamNC27705 United States Departments of Biomedical Engineering Medical Physics Graduate Program and Radiology Carl E. Ravin Advanced Imaging Laboratories Duke University DurhamNC27705 United States Carl E. Ravin Advanced Imaging Laboratories Medical Physics Graduate Program Departments of Radiology Electrical and Computer Engineering Biomedical Engineering and Physics Duke University DurhamNC27705 United States

Objective: This study aims to develop and validate a novel framework, iPhantom, for automated creation of patient-specific phantoms or "digital-twins (DT)" using patient medical images. The framework is applied to assess radiation dose to radiosensitive organs in CT imaging of individual patients. Method: From patient CT images, iPhantom segments selected anchor organs (e.g. liver, bones, pancreas) using a learning-based model developed for multi-organ CT segmentation. Organs challenging to segment (e.g. intestines) are incorporated from a matched phantom template, using a diffeomorphic registration model developed for multi-organ phantom-voxels. The resulting full-patient phantoms are used to assess organ doses during routine CT exams. Result: iPhantom was validated on both the XCAT (n=50) and an independent clinical (n=10) dataset with similar accuracy. iPhantom precisely predicted all organ locations with good accuracy of Dice Similarity Coefficients (DSC) >0.6 for anchor organs and DSC of 0.3-0.9 for all other organs. iPhantom showed Copyright © 2020, The Authors. All rights reserved.

关键词： Phantoms

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Linker Scissoring Strategy Enables Precise Shaping of Metal–Organic Frameworks for Chromatographic Separation

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Angewandte Chemie 2022年第37期134卷

作者： Dr. Ming Xu Dr. Peiyu Cai Sha-Sha Meng Yihao Yang De-Sheng Zheng Prof. Qing-Hua Zhang Prof. Lin Gu Prof. Hong-Cai Zhou Prof. Zhi-Yuan Gu Jiangsu Key Laboratory of Biofunctional Materials Jiangsu Collaborative Innovation Center of Biomedical Functional Materials Jiangsu Key Laboratory of New Power Batteries College of Chemistry and Materials Science Nanjing Normal University Nanjing 210023 China Department of Chemistry Texas A&M University College Station TX 77843-3255 USA Institute of Physics Chinese Academy of Sciences Beijing 100190 China Department of Materials Science and Engineering Texas A&M University College Station TX 77842 USA

Precise shaping of metal–organic frameworks (MOFs) is significant in both fundamental coordination chemistry and practical applications, such as catalysis, separation, and biomedicine. Herein, we demonstrated a linker scissoring strategy for precisely shaping MOFs through surface conformational pairing. In this strategy, the bidentate linkers which were designed according to the original tetratopic ligands and the coordination environment of MOF surfaces, were utilized as the covering agents. The shape of these covering agents and the surface conformation of metals onto MOFs restricted them to coordinate on specific MOF facets thus precisely controlling the shape of the MOFs. Different shapes of PCN-608 from nanoplate (PCN-NP) to nanorod (PCN-NR) have been targeted by adding different bidentate linkers. The universality of this strategy was demonstrated by controlling the shapes of the NU-MOFs from nanoplate to nanorod. This strategy provides a new guiding principle to synthesize MOF nanocrystals with controlled shapes.

关键词： Design Linker Scissoring Metal–Organic Frameworks Separation Shaping

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Real-time density functional tight binding: A new computational tool for probing electronic properties of plasmonic systems 11

Real-time density functional tight binding: A new computatio...

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11th Annual TechConnect World Innovation Conference and Expo, Held Jointly with the 20th Annual Nanotech Conference and Expo,the 2018 SBIR/STTR Spring Innovation Conference, and the Defense TechConnect DTC Spring Conference

作者： Ilawe, Niranjan V. Wong, Bryan M. Department of Chemical and Environmental Engineering Materials Science and Engineering Program University of California - Riverside RiversideCA United States

ISBN: (纸本)9780998878256

Using large-scale, real-time, quantum dynamics calculations, we present a detailed analysis of electronic excitation transfer (EET) mechanisms in a multiparticle plasmonic nanoantenna system. Specifically, we utilize a real-time, time-dependent, density functional tight binding (RT-TDDFTB) approach to provide a quantummechanical description (at an electronic/atomistic level of detail) for characterizing and analyzing these systems, without recourse to classical approximations. We also demonstrate highly long-range electronic couplings in these complex systems and find that the range of these couplings is more than twice the conventional cutoff limit considered by Förster resonance energy transfer (FRET)-based approaches. Furthermore, we attribute these unusually long-ranged electronic couplings to the coherent oscillations of conduction electrons in plasmonic nanoparticles. This long-range nature of plasmonic interactions has important ramifications for EET;in particular, we show that the commonly used "nearestneighbor" FRET model is inadequate for accurately characterizing EET even in simple plasmonic antenna systems. These findings provide a real-time, quantummechanical perspective for understanding EET mechanisms and provide guidance in enhancing plasmonic properties in artificial light-harvesting systems. © 2018 by TechConnect. All rights reserved.

关键词： Plasmonics

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Titelbild: Linker Scissoring Strategy Enables Precise Shaping of Metal–Organic Frameworks for Chromatographic Separation (Angew. Chem. 37/2022)

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Angewandte Chemie 2022年第37期134卷

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Perspective: Mechanical properties of stabilized nanocrystalline FCC metals

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Journal of Applied Physics 2019年第11期126卷

作者： Spearot, Douglas E. Tucker, Garritt J. Gupta, Ankit Thompson, Gregory B. Department of Mechanical and Aerospace Engineering University of Florida GainesvilleFL32611 United States Department of Mechanical Engineering Materials Science Program Colorado School of Mines GoldenCO80401 United States Department of Metallurgical and Materials Engineering University of Alabama TuscaloosaAB35487 United States

In this perspective, recent advances and current research challenges concerning the mechanical properties of stabilized nanocrystalline face-centered cubic (FCC) metals are discussed. First, a brief review of key experiments and modeling efforts over the last two decades is provided, with a focus on elucidating the mechanisms associated with plastic yield, hardening, and microstructure stabilization in nanocrystalline metals. This prior work has provided an understanding of the transition between dislocation-based and grain boundary-mediated mechanisms in plasticity and has identified several strategies to mitigate temperature or stress driven grain growth. Yet, the consequence of various stabilization methods on mechanical properties is not well understood. Future research challenges are presented in order to address this scientific gap, most critically the need to include grain boundary chemistry or grain boundary phases resulting from stabilization methods in new mechanistic theories for mechanical properties of nanocrystalline FCC metals. © 2019 Author(s).

关键词： Grain boundaries

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Approaching the limits of optoelectronic performance in mixed cation mixed halide perovskites by controlling surface recombination

arXiv

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arXiv 2020年

作者： Jariwala, Sarthak Burke, Sven Dunfield, Sean Shallcross, Clayton Taddei, Margherita Wang, Jian Eperon, Giles E. Armstrong, Neal R. Berry, Joseph J. Ginger, David S. Department of Chemistry University of Washington SeattleWA98195 United States Department of Materials Science and Engineering University of Washington SeattleWA98195 United States National Renewable Energy Laboratory GoldenCO80401 United States Materials Science & Engineering Program University of Colorado Boulder BoulderCO80309 United States Department of Chemistry and Biochemistry University of Arizona TucsonAZ85721 United States Swift Solar Inc. San CarlosCA94070 United States

We demonstrate the critical role of surface recombination in mixed-cation, mixed-halide perovskite, FA0.83Cs0.17Pb(I0.85Br0.15)3. By passivating non-radiative defects with the polymerizable Lewis base (3-aminopropyl)trimethoxysilane (APTMS) we transform these thin films. We demonstrate average minority carrier lifetimes > 4 μs, nearly single exponential monomolecular PL decays, and concomitantly high external photoluminescence quantum efficiencies (>20%, corresponding to ~97% of the maximum theoretical quasi-Fermi-level splitting) at low excitation fluence. We confirm both the composition and valence band edge position of the FA0.83Cs0.17Pb(I0.85Br0.15)3 perovskite using multi-institution, cross-validated, XPS and UPS measurements. We extend the APTMS surface passivation to higher bandgap double cation (FA,Cs) compositions (1.7 eV, 1.75 eV and 1.8 eV) as well as the widely used triple cation (FA,MA,Cs) composition and observe significant PL and PL lifetime improvements after surface passivation. Finally, we demonstrate that the average surface recombination velocity (SRV) decreases from ~1000 cm/s to ~10 cm/s post APTMS passivation for FA0.83Cs0.17Pb(I0.85Br0.15)3. Our results demonstrate that surface-mediated recombination is the primary non-radiative loss pathway in MA-free mixed-cation mixed-halide films with a range of different bandgaps, which is a problem observed for a wide range of perovskite active layers and reactive electrical contacts. This study indicates that surface passivation and contact engineering will enable near-theoretical device efficiencies with these materials. Copyright © 2020, The Authors. All rights reserved.

关键词： Passivation

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