Effect of Guest Substitution on Thermoelectric Properties of Clathrate Compounds
Effect of Guest Substitution on Thermoelectric Properties of Clathrate Compounds
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客体取代对笼形化合物热电性能的影响
DOI：
10.1109/ict.2006.331264
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
K. Matsubara
中科院分区：
文献类型：
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作者：
H. Anno;H. Fukushima;K. Koga;K. Okita;K. Matsubara
我们研究了分子式为Ba<sub>8-x</sub>A<sub>x</sub>Au<sub>6</sub>Ge<sub>40</sub>(A=Sr，Eu；标称x=0-4)的多晶客体取代笼状化合物的电学和热电性质。化合物表现出p型导电和简并半导体行为。Seebeck系数和电导率受客体取代的影响不大，表现出与p型Ba<sub>8</sub>Au<sub>x</sub>Ge<sub>46-x</sub>.类似的载流子浓度依赖关系载流子有效质量相对较大，并且还依赖于载流子浓度，如对于p型Ba8Au xGe 46-x的情况。价带X射线光电子能谱研究和能带结构计算表明，具有局域化性质的客体Eu4f态位于离价带顶部约1.5 eV以下，表明Eu替代对p型输运性质的影响可能较小。当x=2时，晶格热导率kappa<SUB>L</SUB>随客体成分的增加而显著降低，Eu替代的Kappa<SUB>L</SUB>的降幅大于锶替代的降幅。结果，与p型Ba8、Au、Au、Ge、46-x相比，热电优值系数ZT得到了提高
We have investigated the electronic and thermoelectric properties of polycrystalline guest-substituted clathrate compounds with the formula Ba<sub>8-x</sub>A<sub>x</sub>Au<sub>6</sub>Ge<sub>40</sub> (A = Sr, Eu; nominal x = 0-4). The compounds show p-type conduction and degenerated semiconductor behavior. The Seebeck coefficient and the electrical conductivity are not largely affected by guest substitution and exhibit carrier concentration dependence that is similar to that for p-type Ba<sub>8</sub>Au<sub>x</sub>Ge<sub>46-x</sub>. The carrier effective mass is relatively large, and also depends on the carrier concentration, as is the case for p-type Ba<sub>8</sub>Au<sub>x</sub>Ge <sub>46-x</sub>. The valence band x-ray photoelectron spectroscopy study and band structure calculation show that the guest Eu 4f states with localized nature are located below about 1.5 eV from the valence band top, suggesting that the influence of Eu substitution on the p-type transport properties may be small. The lattice thermal conductivity kappa<sub>L</sub> decreases greatly with increasing guest composition up to x = 2, and the reduction of kappa<sub>L</sub> for Eu substitution is larger than that for Sr substitution. As a result, thermoelectric figure of merit ZT is improved as compared to that for p-type Ba<sub>8</sub>Au<sub>x</sub>Ge<sub>46-x</sub>
DOI：
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发表时间：
2004
期刊：
IEEE Proc.23rd Int.Conf.on Thermoelectrics (ICT2004) (印刷中)
影响因子：
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作者：
君家;西籔;横田;平;富田;柳澤;外園昌弘;M.Hokazono;H.Anno
通讯作者：
H.Anno