共查询到19条相似文献,搜索用时 93 毫秒
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碲化铋(Bi2Te3)作为近室温区热电性能最好的材料之一,在电子器件、航空航天等领域具有广阔的应用前景。但该材料热电转换效率较低,制约了其规模化工业应用。因此,如何提高Bi2Te3材料的热电转换效率成为重点关注的问题。在Bi2Te3材料中掺杂不同的元素或第二相,通过调整材料的晶体结构、化学组分及能带结构,调控载流子浓度和迁移率,降低热导率,可提高材料的热电性能。依据Bi2Te3热电材料的结构、性质及掺杂改性原理,以掺杂元素或第二相种类和数量作为切入点,总结了目前的部分研究成果,探讨掺杂对Bi2Te3材料热电性能的影响,并指出了今后的研究重点及方向。 相似文献
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热电能量采集器是一种基于塞贝克效应,利用温差将热能直接转化成电能的温差发电装置.由于其体积小、重量轻、寿命长、无机械运动部件、绿色环保等优点,微型热电能量采集器(MTEG)已经引起了国内外的广泛关注.综述了微型热电能量采集器在国内外的研究进展,介绍了温差发电的工作原理,从热电材料和器件结构两方面重点探讨了微型热电能量采集器的研究现状.对微型热电能量采集器未来的发展方向进行了分析和预测,认为积极寻找具有高优值系数的热电材料制备易于加工和集成的高性能的微型热电能量采集器是未来研究工作的目标.微型热电能量采集器有广阔的应用前景. 相似文献
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压电晶体是1880~1930年采用的器件,其中KDP、ADP、BaTiO_3及陶瓷晶体PZT等在1915年发现,并应用它们的压电效应,热电晶体具有可逆极化(称为铁电晶体),目前已发现铁电材料的品种多于1000种,其中多数性能已被研究过.随着对热电材料及器件工艺的深入研究,根据热电探测器R_v∝d的关系(R_v:器件响应,d:材料厚度),和要求器件高性能与低成本的原则,目前主要集中研制直 相似文献
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热电制冷(TEC)已成为制冷领域的一个重要发展方向,但是由于其转换效率过低且材料成本较高,目前难以得到广泛应用。对热电制冷技术进行了简要介绍,并综述了热电制冷技术的研究进展,包括热电材料、结构优化和散热方式。讨论并分析了有机热电材料和无机热电材料的热电性能、不同结构设计所导致的性能系数、不同散热方式对制冷效率的影响。最后,对热电制冷技术的优化进行了简单总结,只有不断提高热电材料的优值系数,并选择合适的结构设计和散热方式,才能使热电制冷技术在各个领域拥有更大的发展空间。 相似文献
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综述了NaxCo2O4系、ZnO系和CuAlO2系氧化物热电材料的晶体结构、制备方法和研究现状,发现这三类热电材料均具有较好的热电性能,具有进一步研究的价值。阐述了金属氧化物热电材料未来的研究方向。 相似文献
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Eric S. Toberer Alexandra Zevalkink Nicole Crisosto G. Jeffrey Snyder 《Advanced functional materials》2010,20(24):4375-4380
Understanding transport in Zintl compounds is important due to their unusual chemistry, structural complexity, and potential for good thermoelectric performance. Resistivity measurements indicate that undoped Ca5Al2Sb6 is a charge‐balanced semiconductor with a bandgap of 0.5 eV, consistent with Zintl–Klemm charge counting rules. Substituting divalent calcium with monovalent sodium leads to the formation of free holes, and a transition from insulating to metallic electronic behavior is observed. Seebeck measurements yield a hole mass of ~2me, consistent with a structure containing both ionic and covalent bonding. The structural complexity of Zintl compounds is implicated in their unusually low thermal conductivity values. Indeed, Ca5Al2Sb6 possesses an extremely low lattice thermal conductivity (0.6 W mK?1 at 850 K), which approaches the minimum thermal conductivity limit at high temperature. A single parabolic band model is developed and predicts that Ca4.75Na0.25Al2Sb6 possesses a near‐optimal carrier concentration for thermoelectric power generation. A maximum zT > 0.6 is obtained at 1000 K.Beyond thermoelectric applications, the semiconductor Ca5Al2Sb6 possesses a 1D covalent structure which should be amenable to interesting magnetic interactions when appropriately doped. 相似文献
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Catherine A. Cox Shawna R. Brown G. Jeffrey Snyder Susan M. Kauzlarich 《Journal of Electronic Materials》2010,39(9):1373-1375
Complex Zintl phases possess low thermal conductivity and can be easily doped to modify the transport properties. Therefore,
these phases have the potential to be good thermoelectric materials by simply controlling carrier concentration. Yb14MnSb11 is a Zintl phase that has shown promise as a p-type thermoelectric material for high-temperature power generation. A Sn-flux synthetic route was used to make the new phase,
Yb13CaMnSb11. The high-temperature thermoelectric properties were measured on polycrystalline hot-pressed pellets and compared with Yb14MnSb11. Substitution of the lighter isovalent Ca for Yb should reduce the lattice thermal conductivity by mass disorder scattering,
and a noticeable reduction is seen in thermal diffusivity measurements at high temperature. There may also be a carrier concentration
effect by employing the more electropositive Ca. 相似文献
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We calculated electronic structures and transport properties of 33 Zintl phase compounds M1M2X (M1, M2 = Li, Na, Mg, K, Ca, Rb, Sr, Ba; X = Si, Ge, As, Se, Sn, Sb, Te, Pb, Bi) having orthorhombic MgSrSi-type (PbCl2-type) structure. These compounds were calculated to be narrow-gap semiconductors or semimetals. By comparison with known thermoelectric materials, our analysis showed that these compounds are promising candidate new thermoelectric materials, when heavily doped with holes or electrons. The weak chemical bonds and the variety in constituent elements indicate the possibility to achieve high thermoelectric figure of merit. 相似文献
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Zintl Phases as Thermoelectric Materials: Tuned Transport Properties of the Compounds CaxYb1–xZn2Sb2
F. Gascoin S. Ottensmann D. Stark S.M. Haïle G.J. Snyder 《Advanced functional materials》2005,15(11):1860-1864
Zintl phases are ideal candidates for efficient thermoelectric materials, because they are typically small‐bandgap semiconductors with complex structures. Furthermore, such phases allow fine adjustment of dopant concentration without disrupting electronic mobility, which is essential for optimizing thermoelectric material efficiency. The tunability of Zintl phases is demonstrated with the series CaxYb1–xZn2Sb2 (0 ≤ x ≤ 1). Measurements of the electrical conductivity, Hall mobility, Seebeck coefficient, and thermal conductivity (in the 300–800 K temperature range) show the compounds to behave as heavily doped semiconductors, with transport properties that can be systematically regulated by varying x. Within this series, x = 0 is the most metallic (lowest electrical resistivity, lowest Seebeck coefficient, and highest carrier concentration), and x = 1 is the most semiconducting (highest electrical resistivity, highest Seebeck coefficient, and lowest carrier concentration), while the mobility is largely independent of x. In addition, the structural disorder generated by the incorporation of multiple cations lowers the overall thermal conductivity significantly at intermediate compositions, increasing the thermoelectric figure of merit, zT. Thus, both zT and the thermoelectric compatibility factor (like zT, a composite function of the transport properties) can be finely tuned to allow optimization of efficiency in a thermoelectric device. 相似文献
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Xun Shi Jiong Yang Shengqiang Bai Jihui Yang Hsin Wang Miaofang Chi James R. Salvador Wenqing Zhang Lidong Chen Winnie Wong‐Ng 《Advanced functional materials》2010,20(5):755-763
Type I clathrates have recently been identified as prospective thermoelectric materials for power generation purposes due to their very low lattice thermal conductivity values. The maximum thermoelectric figure of merit of almost all type I clathrates is, however, less than 1 and occurs at, or above, 1000 K, making them unfavorable especially for intermediate temperature applications. In this report, the Zintl–Klemm rule is demonstrated to be valid for Ni, Cu, and Zn transition metal substitution in the framework of type I clathrates and offers many degrees of freedom for material modification, design, and optimization. The cross‐substitution of framework elements introduces ionized impurities and lattice defects into these materials, which optimize the scattering of charge carriers by the substitution‐induced ionized impurities and the scattering of heat‐carrying lattice phonons by point defects, respectively, leading to an enhanced power factor, reduced lattice thermal conductivity, and therefore improved thermoelectric figure of merit. Most importantly, the bandgap of these materials can be tuned between 0.1 and 0.5 eV by adjusting the cross‐substitution ratio of framework elements, making it possible to design clathrates with excellent thermoelectric properties between 500 and 1000 K. 相似文献
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Tsutomu Kanno Hiromasa Tamaki Masato Yoshiya Hiroshi Uchiyama Sachiko Maki Masaki Takata Yuzuru Miyazaki 《Advanced functional materials》2021,31(13):2008469
Mg3Sb2-based intermetallic compounds with exceptionally high thermoelectric performance exhibit unconventional n-type dopability and anomalously low thermal conductivity, attracting much attention to the underlying mechanisms. To date, investigations have been limited to first-principle calculations and thermodynamic analysis of defect formation, and detailed experimental analysis on crystal structure and phonon modes has not been achieved. Here, a synchrotron X-ray diffraction study clarifies that, against a previous view of a simple crystal structure with a small unit cell, Mg3Sb2 is inherently a heavily disordered material with Frenkel defects, charge-neutral defect complexes of cation vacancies and interstitials. Ionic charge neutrality preserved in Mg3Sb2 is responsible for exotic n-type dopability, which is unachievable for other Zintl phase materials. The thermal conductivity of Mg3Sb2 exhibits deviation from the standard T−1 temperature dependency with strongly limited phonon transport due to a strain field. Inelastic X-ray scattering measurement reveals enhanced phonon scattering induced by disorder. The results will draw renewed attention to crystal defects and disorder as means to explore new high-performance thermoelectric materials. 相似文献
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Zilu Liu Tianjun Liu Christopher N. Savory Jos P. Jurado Juan Sebastin Reparaz Jianwei Li Long Pan Charl F. J. Faul Ivan P. Parkin Gopinathan Sankar Satoru Matsuishi Mariano Campoy‐Quiles David O. Scanlon Martijn A. Zwijnenburg Oliver Fenwick Bob C. Schroeder 《Advanced functional materials》2020,30(32)
Organometallic coordination polymers (OMCPs) are a promising class of thermoelectric materials with high electrical conductivities and thermal resistivities. The design criteria for these materials, however, remain elusive and so far material modifications have been focused primarily on the nature of the metal cation to tune the thermoelectric properties. Herein, an alternative approach is described by synthesizing new organic ligands for OMCPs, allowing modulation of the thermoelectric properties of the novel OMCP materials over several orders of magnitude, as well as controlling the polarity of the Seebeck coefficient. Extensive material purification combined with spectroscopy experiments and calculations furthermore reveal the charge‐neutral character of the polymer backbones. In the absence of counter‐cations, the OMCP backbones are composed of air‐stable, ligand‐centered radicals. The findings open up new synthetic possibilities for OMCPs by removing structural constraints and putting significant emphasis on the molecular structure of the organic ligands in OMCP materials to tune their thermoelectric properties. 相似文献
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H. Takiguchi Z. Yoshikawa H. Miyazaki Y. Okamoto J. Morimoto 《Journal of Electronic Materials》2010,39(9):1627-1633
Amorphous Si-Ge-Au thin films exhibit high thermoelectric power. To understand the role of Au in the thermoelectric properties,
we studied the structural and thermoelectric properties of Si/Au and Ge/Au thin films. Samples were prepared by electron beam
evaporation. Au was found to have two important roles. One is as a carrier source. Therefore, Au composition influences thermoelectric
properties. The other role is that Au causes the crystallization of Si and Ge at lower temperature. The grain size ranged
from ten to a few tens of nanometers. We conclude that the fine structure is important for high thermoelectric performance. 相似文献
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The semi-analytical methods of thermoelectric energy conversion efficiency calculation based on the cumulative properties approach and reduced variables approach are compared for 21 high performance thermoelectric materials. Both approaches account for the temperature dependence of the material properties as well as the Thomson effect, thus the predicted conversion efficiencies are generally lower than that based on the conventional thermoelectric figure of merit ZT for nearly all of the materials evaluated. The two methods also predict material energy conversion efficiencies that are in very good agreement which each other, even for large temperature differences (average percent difference of 4% with maximum observed deviation of 11%). The tradeoff between obtaining a reliable assessment of a material’s potential for thermoelectric applications and the complexity of implementation of the three models, as well as the advantages of using more accurate modeling approaches in evaluating new thermoelectric materials, are highlighted. 相似文献