Vacancy scattering for enhancing the thermoelectric performance of CuGaTe2 solid solutions
Vacancy scattering for enhancing the thermoelectric performance of CuGaTe2 solid solutions
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空位散射增强 CuGaTe2 固溶体热电性能
DOI：
10.1039/c6ta06033a
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发表时间：
2016-01-01
影响因子：
11.9
通讯作者：
Pei, Yanzhong
中科院分区：
文献类型：
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作者：
Shen, Jiawen;Zhang, Xinyue;Pei, Yanzhong
长期以来，通过点缺陷的有效声子散射来提高热电性能在许多材料中都被证明是成功的。这种类型的声子散射依赖于主原子和客原子之间的质量和应变涨落，当主导点缺陷为空位时，这两个涨落都可以最大化。除了一些化合物本质上的固有空位外，由于基质化合物的晶体结构需要稳定，与基质相比，阳离子与阴离子比较小的溶剂形成的固溶体预计会产生空位。在这项工作中，选择了与CuGaTe2基质相比阳离子比较小的In2Te3和Ga(2)Te(3)I作为分子溶剂来形成固溶体。由此产生的高浓度空位可以作为声子散射中心，显著降低了晶格的热导率，从而在整个温度范围内提高了高达75%的热电性能。这项工作展示了一种通过在固溶体中产生空位来提高热电性能的有用策略。
Enhancing the thermoelectric performance through an effective phonon scattering by point defects has long been proven to be successful in many materials. This type of phonon scattering relies on the mass and strain fluctuations between the host and guest atoms, both of which can be maximized when the dominant point defects are vacancies. Besides the intrinsic vacancies in some compounds by nature, the formation of solid solutions with a solvent having a smaller cation-to-anion ratio as compared to the matrix is expected to create vacancies because the crystal structure needs to be stabilized in that of the matrix compound. In this work, In2Te3 and Ga(2)Te(3)i, compounds with a smaller cation-to-anion ratio as compared to the CuGaTe2 matrix, are chosen as molecular solvents to form solid solutions. The resulting high concentration vacancies on the cation sites, which can act as the phonon scattering centers, significantly reduce the lattice thermal conductivity and therefore enhance the thermoelectric performance by up to similar to 75% in the entire temperature range. This work demonstrates a useful strategy for enhancing thermoelectric performance by vacancy creation in solid solutions.