共查询到12条相似文献,搜索用时 0 毫秒
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Bi2Te3热电材料研究现状 总被引:1,自引:0,他引:1
Bi2Te3热电材料是半导体材料,室温下具有良好的热电特性,能够实现热能和电能的相互转化,应用前景十分广阔。Bi2Te3热电材料的转换效率低是影响其应用的瓶颈之一,目前世界范围内的研究热点主要集中在如何提高热电材料的能量转换效率上。综述了热电材料的种类、国内外关于Bi2Te3热电薄膜的制备方法和性能研究,对多种典型制备方法进行分析对比,探讨了影响Bi2Te3热电薄膜质量的因素及机制。结合Bi2Te3热电薄膜在温差发电和热电制冷方面的应用,如果微型热电制冷器实现与大功率LED芯片集成封装,那么芯片级低温散热问题有望解决。 相似文献
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Bi2Te3薄膜是室温下热电性能最好的热电材料,利用磁控溅射在长有一薄层SiO2的n型硅样品上制备Bi/Te多层复合薄膜,经后续退火处理生成Bi2Te3。通过分析Bi2Te3薄膜的生长和退火工艺,探讨Bi/Te中Te的原子数分数对薄膜热电性能的影响。采用XRD和SEM对薄膜的结构、形貌和成分进行分析,并测量不同条件下的Seebeck系数。薄膜Seebeck系数均为负数,表明所制备样品是n型半导体薄膜,且最大值达到-76.81μV.K-1;电阻率ρ随Te的原子数分数增大而增大,其趋势先缓慢后迅速。Bi2Te3薄膜的热电性能良好,Te的原子数分数是60.52%时,功率因子最大,为1.765×10-4W.K-2.m-1。 相似文献
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T. W. Lan Y. C. Chen J. C. Ho S. G. Shyu Y. Y. Chen 《Journal of Electronic Materials》2012,41(9):2326-2330
This study examines the thermoelectric behavior of composites containing hydrothermally processed tellurium-coated bismuth particles of various sizes. Since only a very thin layer of Bi2Te3 forms on the particle surface, the high-pressure compacted composite is still dominated by bismuth as the main ingredient (??96% Bi). Thermoelectric figure of merit ZT values are derived from measurements of thermal conductivity, electrical resistivity, and Seebeck coefficient. As expected, a ZT value almost three times higher than that of bismuth is found. This enhancement appears to be caused mainly by lowered thermal conductivity due to the significant number of grain boundaries, short phonon mean free path in the coating layers, and lattice mismatch. 相似文献
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We have developed a modified Harman method to extract the thermoelectric signal using a squared AC current in the presence
of Joule heating, and have measured the thermal conductivity and dimensionless figure of merit of single crystals of the layered
rhodium oxide Bi0.78Sr0.4RhO3+d
and the pseudo-one-dimensional rhodium oxide Ba1.2Rh8O16. We find that these rhodium oxides exhibit a small thermal conductivity of 30 mW/cm K at 200 K and rather large ZT of 0.02 below 200 K. We believe that this method will be a powerful tool for thermal conductivity measurements in sub-millimeter-sized
crystals. 相似文献
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Teng Fang Xin Li Chaoliang Hu Qi Zhang Jiong Yang Wenqing Zhang Xinbing Zhao David J. Singh Tiejun Zhu 《Advanced functional materials》2019,29(28)
Bi2Te3‐based compounds and derivatives are milestone materials in the fields of thermoelectrics (TEs) and topological insulators (TIs). They have highly complex band structures and interesting lattice dynamics, which are favorable for high TE performance as well as strong spin orbit and band inversion underlying topological physics. This review presents rational calculations of properties related to TEs and provides theoretical guidance for improving the TE performance of Bi2Te3‐based materials. Although the band structures of these TE materials have been studied theoretically and experimentally for many years, there remain many controversies on band characteristics, especially the locations of band extrema and the exact values of bandgaps. Here, the key factors in the theoretical investigations of Bi2Te3, Bi2Se3, Sb2Te3, and their solid solutions are reviewed. The phonon spectra and lattice thermal conductivities of Bi2Te3‐based materials are discussed. Electronic and phonon structures and TE transport calculations are discussed and reported in the context of better establishing computational parameters for these V2VI3‐based materials. This review provides a useful guidance for analyzing and improving TE performance of Bi2Te3‐based materials. 相似文献
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Bruce A. Cook Matthew J. Kramer Joel L. Harringa Mi‐Kyung Han Duck‐Young Chung Mercouri G. Kanatzidis 《Advanced functional materials》2009,19(8):1254-1259
Thermoelectric materials based on quaternary compounds Ag1?xPbmSbTe2+m exhibit high dimensionless figure‐of‐merit values, ranging from 1.5 to 1.7 at 700 K. The primary factor contributing to the high figure of merit is a low lattice thermal conductivity, achieved through nanostructuring during melt solidification. As a consequence of nucleation and growth of a second phase, coherent nanoscale inclusions form throughout the material, which are believed to result in scattering of acoustic phonons while causing only minimal scattering of charge carriers. Here, characterization of the nanosized inclusions in Ag0.53Pb18Sb1.2Te20 that shows a strong tendency for crystallographic orientation along the {001} planes, with a high degree of lattice strain at the interface, consistent with a coherent interfacial boundary is reported. The inclusions are enriched in Ag relative to the matrix, and seem to adopt a cubic, 96 atom per unit cell Ag2Te phase based on the Ti2Ni type structure. In‐situ high‐temperature synchrotron radiation diffraction studies indicated that the inclusions remain thermally stable to at least 800 K. 相似文献
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Composite films of polyacrylonitrile (PAN) and multiwalled carbon nanotubes (MWNTs) have been prepared by gelation/crystallization from solution. The contents of MWNTs were 5–10 wt.‐%, measured against PAN. The electrical and mechanical properties have been studied in comparison with those of the homopolymer PAN films prepared from the same method. Furthermore, stabilization and the carbonization have been carried out by using the drawn PAN–MWNTs as a new precursor to prepare carbon films with a cross‐sectional area much larger than that of a commercial carbon fiber (> 3000 times). The MWNTs within the PAN matrix promote the formation of a condensed aromatic ladder structure during the stabilization process and play an important role in preparing PAN‐based carbon material with high carbon quality and high mechanical properties. When the stabilized composites with 10 wt.‐% MWNTs are carbonized at 1000 °C, the Young's modulus reaches 37.5 GPa, and the electrical conductivity reaches 102 S cm–1. The carbonized PAN homopolymer does not form an adequately robust bulk film for the mechanical properties to be measured. 相似文献
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L.‐Z. Fan Y.‐S. Hu J. Maier P. Adelhelm B. Smarsly M. Antonietti 《Advanced functional materials》2007,17(16):3083-3087
A high‐performance polyaniline electrode was prepared by potentiostatic deposition of aniline on a hierarchically porous carbon monolith (HPCM), which was carbonized from the mesophase pitch. A capacitance value as high as 2200 F g–1 (per weight of polyaniline) is obtained at a power density of 0.47 kW kg–1 and an energy density of 300 W h kg–1. This active material deposited on HPCM also has the advantageous of high stability. These properties can be essentially attributed to the backbone role of HPCM. The method also has the advantage of a topology that is favorable for kinetics at high power densities, thus, contributing to the increase of ionic conductivity and power density. There is also no need for a binder, which not only lowers the preparation costs but also offers advantages in terms of stability and performance. 相似文献
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Versatile Electronic Skins for Motion Detection of Joints Enabled by Aligned Few‐Walled Carbon Nanotubes in Flexible Polymer Composites 下载免费PDF全文
Hongfei Zhu Xuewen Wang Jia Liang Hongling Lv Huayu Tong Lianbo Ma Yi Hu Guoyin Zhu Ting Zhang Zuoxiu Tie Zheng Liu Qingwen Li Liwei Chen Jie Liu Zhong Jin 《Advanced functional materials》2017,27(21)
Here, novel multifunctional electronic skins (E‐skins) based on aligned few‐walled carbon nanotube (AFWCNT) polymer composites with a piezoresistive functioning mechanism different from the mostly investigated theory of “tunneling current channels” in randomly dispersed CNT polymer composites are demonstrated. The high performances of as‐prepared E‐skins originate from the anisotropic conductivity of AFWCNT array embedded in flexible composite and the distinct variation of “tube‐to‐tube” interfacial resistance responsive to bending or stretching. The polymer/AFWCNT‐based flexion‐sensitive E‐skins exhibit high precision and linearity, together with low power consumption (<10 µW) and good stability (no degradation after 15 000 bending–unbending cycles). Moreover, polymer/AFWCNT composites can also be used for the construction of tensile‐sensitive E‐skins, which exhibit high sensitivity toward tensile force. The polymer/AFWCNT‐based E‐skins show remarkable performances when applied to monitor the motions and postures of body joints (such as fingers), a capability that can find wide applications in wearable human–machine communication interfaces, portable motion detectors, and bionic robots. 相似文献
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Advanced 3D carbon-based electrodes have the potential to significantly enhance the energy-power density of lithium ion batteries and sodium ion batteries, due to their continuous conductive networks, proper porosity distribution, and integrated stable structure. However, it still remains a fundamental scientific challenge to accurately understand the charge/ion transport in 3D carbon-based electrodes. In this review, the operating mechanism of charge/ion transport in 3D carbon-based electrodes are comprehended by introducing a useful architectural analogy to provide a physical insight. In order to better understand the relationship between 3D carbon-based electrode structure and electrode process characteristics, the main design strategies of 3D carbonbased electrodes according to the specific characteristic of pore tortuosity is proposed. Through analysis of 3D carbon electrode architectural models, several key scientific issues and related characterization technologies that are beneficial to improving the charge/ion transport efficiency are also raised. The kinetics difference of ionic transport between Li+ and Na+ ions is also taken into account. Furthermore, the critical parameters of porous structure including porosity and tortuosity to investigate the parameter-structure-performance relationships of 3D carbon-based architecture electrodes are highlighted, which in turn would guide more rational battery design in tradeoff between the high capacity and fast transport. 相似文献