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Suppressed Thermal Conductivity in polycrystalline Gold Nanofilm:The Effect of Grain Boundary and Substrate

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Chinese Physics Letters 2021年第2期38卷 78-83页

作者： Lan Dong Xiangshui Wu Yue Hu Xiangfan Xu Hua Bao University of Michigan-Shanghai Jiao Tong University Joint Institute Shanghai Jiao Tong UniversityShanghai 200240China Center for Phononics and Thermal Energy Science China-EU Joint Center for NanophononicsSchool of Physics Science and EngineeringTongji University200092 Shanghai 200092China

We investigate the electrical conductivity and thermal conductivity of polycrystalline gold nanofilms,with thicknesses ranging from 40.5nm to 115.8 nm,and identify a thickness-dependent electrical conductivity,which can be explained via the Mayadas and Shatzkes(MS)*** the same time,a suppressed thermal conductivity is observed,as compared to that found in the bulk material,together with a weak thickness *** compare the thermal conductivity of suspended and supported gold films,finding that the supporting substrate can effectively suppress the in-plane thermal conductivity of the polycrystalline gold *** results indicate that grain boundary scattering and substrate scattering can affect electron and phonon transport in polycrystalline metallic systems.

关键词： conductivity polycrystalline scattering

Quantification of electron accumulation at grain boundaries in perovskite polycrystalline films by correlative infrared-spectroscopic nanoimaging and Kelvin probe force microscopy

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Light(Science & Applications) 2021年第5期10卷 890-897页

作者： Ting-Xiao Qin En-Ming You Mao-Xin Zhang Peng Zheng Xiao-Feng Huang Song-Yuan Ding Bing-Wei Mao Zhong-Qun Tian State Key Laboratory of Physical Chemistry of Solid Surfaces Collaborative Innovation Center of Chemistry for Energy MaterialsCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamenChina School of Aerospace Engineering Xiamen UniversityXiamenChina

Organic–inorganic halide perovskites are emerging materials for photovoltaic applications with certified power conversion efficiencies(PCEs)over 25%.Generally,the microstructures of the perovskite materials are critical to the performances of ***,the role of the nanometer-sized grain boundaries(GBs)that universally existing in polycrystalline perovskite films could be benign or detrimental to solar cell performance,still remains ***,nanometer-resolved quantification of charge carrier distribution to elucidate the role of GBs is highly ***,we employ correlative infrared-spectroscopic nanoimaging by the scattering-type scanning near-field optical microscopy with 20 nm spatial resolution and Kelvin probe force microscopy to quantify the density of electrons accumulated at the GBs in perovskite polycrystalline thin *** is found that the electron accumulations are enhanced at the GBs and the electron density is increased from 6×10^(19) cm^(−3 )in the dark to 8×10^(19) cm^(−3 ) under 10 min illumination with 532 nm *** results reveal that the electron accumulations are enhanced at the GBs especially under light illumination,featuring downward band bending toward the GBs,which would assist in electron-hole separation and thus be benign to the solar cell performance.

关键词： illumination polycrystalline grain

Ultrafine polycrystalline titania nanofibers for superior sodium storage

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Journal of Energy Chemistry 2019年第11期28卷 153-161页

作者： Zhidan Diao Daming Zhao Chunxiao Lv Hongli Liu Dongjiang Yang Shaohua Shen International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong UniversityXi’an 710049ShaanxiChina School of Environmental Science and Engineering Collaborative Innovation Centerfor Marine Biomass FibersMaterials and Textiles of Shandong ProvinceQingdao UniversityQingdao 266071ShandongChina

Sodium ion batteries have a huge potential for large-scale energy storage for the low cost and abundance of sodium resources. In this work, a novel structure of ultrafine polycrystalline TiO2 nanofibers is prepared on nickel foam/carbon cloth by a simple vapor deposition method. The as-prepared TiO2 nanofibers show excellent performance when used as anodes for sodium-ion batteries. Specifically, the TiO2 nanofibers@nickel foam electrode delivers a high reversible capacity of 263.2 m Ahg^-1 at 0.2 C and maintains a considerable capacity of 144.2 m Ahg^-1 at 10 C. The TiO2 nanofibers@carbon cloth electrode also shows excellent high-rate capability, sustaining a capacity of 148 m Ahg^-1 after 20 0 0 cycles at 10 C. It is believed that the novel nanofibrous structure increases the contact area with the electrolyte and greatly shortens the sodium ion diffusion distance, and meanwhile, the polycrystalline nature of nanofibers exposes more intercalation sites for sodium storage. Furthermore, the density functional theory calculations exhibit strong ionic interactions between the exposed TiO2(101) facets and sodium ions, leading to a preferable sodiation/desodiation process. The unique structural features endow the TiO2 nanofibers electrodes great advantages in rapid sodium storage with an outstanding high-rate capability.

关键词： polycrystalline titania Nanofibers Sodium storage High-rate capability

Phase-feld Study for Texture Evolution in polycrystalline Materials under Applied Stress

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Journal of Materials Science & Technology 2013年第10期29卷 999-1004页

作者： Yanli Lu Liuchao Zhang Yingying Zhou Zheng Chen Jianguo Zhang State Key Lab of Solidifcation Processing Northwestern Polytechnical University

The formation and evolution of deformation texture in polycrystalline materials are studied by phase-field dynamic model. In addition, the driving force of texture evolution is also discussed. In this model, grains with different orientation are defined by a set of continuous non-conserved order parameter fields. Simulation results show that grains with preferred orientation grow at the expense of those with unfavorable orientations. It is more important that, elastic potentia evolution of texture whether the polycrystalline system rather than elastic energy plays a crucial role in the s subjected to uniaxial stress or shear stress.

关键词： DS: Deformation texture polycrystalline Applied stress Phase-field model

Size-controllable synthesis and high-performance formic acid oxidation of polycrystalline Pd nanoparticles

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Rare Metals 2019年第2期38卷 115-121页

作者： Hui-Hui Wang Jin-Feng Zhang Ze-Lin Chen Meng-Meng Zhang Xiao-Peng Han Cheng Zhong Yi-Da Deng Wen-Bin Hu Tianjin Key Laboratory of Composites and Functional Materials and Key Laboratory of Advanced Ceramics and Machining Technology (Ministry of Education) Tianjin University

A facile approach was developed for the synthesis of polycrystalline palladium nanoparticles(Pd NPs)by using tannic acid(TA) as green reagent and stabilizer in a 30 ℃ water bath. The size of Pd NPs can be tuned in a range of 10–60 nm simply by adjusting the concentration of Pd precursor. The catalytic activity and stability of the as-obtained Pd NPs toward formic acid oxidation were analyzed. It is found that these Pd NPs with different sizes exhibit size-dependent and enhanced formic acid oxidation performance compared to the commercial Pd black catalyst. It should be noted that the Pd catalysts with an average size of 24 nm demonstrate the best catalytic activity and stability among the other prepared Pd NPs, which can be ascribed to its larger electrochemical surface area(ECSA)and polycrystalline structure with defects.

关键词： polycrystalline palladium nanoparticle Size controllable Tannic acid: Room temperature Formic acid oxidation

Features of the Real Structure of Lanthanum Hexaboride polycrystalline

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Chinese Physics Letters 2001年第7期18卷 942-943页

作者： ZHENG Shu-Qi MIN Guang-Hui ZOU Zeng-Da YU Pu-Lian HAN Jian-De Y.B.Paderno College of Materials Science and Engineering Shandong UniversityJi’nan 250061 Institute for Problems of Materials Science National Academy of Sciences of UkraineKiev 03142Ukraine

The Microstructure of lanthanum hexaboride(LaB6)polycrystalline has been studied by using transmission electron *** shows that the ideal LaB6 polycrystalline can be obtained by sintering ingots at the temperature of 2273 K for holding time of 120 min in Ar pressure of 800 Torr,where the ingots are formed by pressing LaB6 powder at room temperature at a pressure of 0.4-0.5 *** particles in LaB6 polycrystalline hardly bind;there are only a few of pores at the joint parts of three particles and a few of impurities exist in some *** sintering process for fabricating LaB6 polycrystalline is analysed and the formation of the pore and the impurities are studied from the point of surface tension.

关键词： LaB6 polycrystalline lanthanum

Graph neural networks for an accurate and interpretable prediction of the properties of polycrystalline materials

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npj Computational Materials 2021年第1期7卷 925-933页

作者： Minyi Dai Mehmet F.Demirel Yingyu Liang Jia-Mian Hu Department of Materials Science and Engineering University of Wisconsin-MadisonMadisonWIUSA Department of Computer Sciences University of Wisconsin-MadisonMadisonWIUSA

Various machine learning models have been used to predict the properties of polycrystalline materials,but none of them directly consider the physical interactions among neighboring grains despite such microscopic interactions critically determining macroscopic material ***,we develop a graph neural network(GNN)model for obtaining an embedding of polycrystalline microstructure which incorporates not only the physical features of individual grains but also their *** embedding is then linked to the target property using a feed-forward neural *** the magnetostriction of polycrystalline Tb_(0.3)Dy_(0.7)Fe_(2) alloys as an example,we show that a single GNN model with fixed network architecture and hyperparameters allows for a low prediction error of~10%over a group of remarkably different microstructures as well as quantifying the importance of each feature in each grain of a microstructure to its *** a microstructure-graph-based GNN model,therefore,enables an accurate and interpretable prediction of the properties of polycrystalline materials.

关键词： microstructure polycrystalline prediction

Study of Thermal Treatment on Properties of polycrystalline Silicon

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Journal of Rare Earths 2006年第z1期24卷 237-240页

作者： Ren Bingyan Gou Xianfang Ma Lifen Li Xudong Xu Ying Wang Wenjing Institute of Information Function Materials Hebei University of Technology Tianjin 300130 China Institute of Information Function Materials Hebei University of Technology Tianjin 300130 China Institute of Information Function Materials Hebei University of Technology Tianjin 300130 China Beijing Solar Energy Research Institute Beijing 100083 China Beijing Solar Energy Research Institute Beijing 100083 China Beijing Solar Energy Research Institute Beijing 100083 China

The effects of thermal annealing on oxygen behavior and carrier lifetimes of mc-Si wafers were investigated by means of FTIR and QSSPCD during single step and two step heat treatments in N2 and O2 ambient. It reveals that interstitial oxygen concentration of mc-Si and CZ-Si has a slighter decrease in N2 and O2 ambient during single-step annealing, which means oxygen precipitates are not generated. But oxygen concentration greatly decreases and generates a number of oxygen precipitates during two-step annealing. Bulk lifetime of mc-Si increases in N2 ambient at 850, 950, 1150 ℃ respectively, and annealing in O2 shows better results than that in N2 and annealing in two-step reflected better consequence than annealing in single-step. But lifetime of CZ-Si annealed in N2 or O2 decreases rapidly. The reason of lifetime increase is probably considered due to the fact that interstitial Si atoms of Si/SiO2 interface fill vacancies or some recombination centers at high temperature annealing. Moreover, a number of impurities in mc-Si probably diffuse to grain boundaries so that greatly reduce recombination centers result to lifetime rising.

关键词： polycrystalline silicon oxygen lifetime

Structure and Wettability Engineering of polycrystalline Diamond Films Treated by Thermally Oxidation,Second Growth and Surface Termination

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Chinese Physics Letters 2022年第3期39卷 49-53页

作者： Linfeng Wan Caoyuan Mu Yaofeng Liu Shaoheng Cheng Qiliang Wang Liuan Li Hongdong Li Guangtian Zou State Key Lab of Superhard Materials College of PhysicsJilin UniversityChangchun 130012China Shenzhen Research Institute Jilin UniversityShenzhen 518057China

High-quality polycrystalline diamond films with dominated(100)-oriented grains are realized by combining the thermally oxidation and the homogeneous second growth ***,we investigate the wettability property of the polycrystalline diamonds in various *** surface structures(with various grain sizes,voids,and orientations,etc.)and terminations(hydrogen or oxygen)have significant effects on the wettability of polycrystalline diamond *** wettability is further closely related to the polarity of *** measuring the contact angle and calculating the dispersion and polarity components,we estimate the surface energy of polycrystalline diamond films,and explore the factors affecting the surface *** modulations in growth quality and wettability property of polycrystalline diamond films provide valuable data for development of diamond-based multiple devices in practical applications.

关键词： polycrystalline property Diamond