Vacancy engineering in rock-salt type (IV-VI)x(V-VI) materials for high thermoelectric performance
Vacancy engineering in rock-salt type (IV-VI)x(V-VI) materials for high thermoelectric performance
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DOI：
10.1016/j.nanoen.2020.105198
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发表时间：
2020-12
期刊：
影响因子：
17.6
通讯作者：
Y. Min;Minkyung Kim;Geon‐Tae Hwang;C. Ahn;Jong‐Jin Choi;B. Hahn;W. Yoon;G. Moon;Chee-Sung Park-Chee-Sun
中科院分区：
文献类型：
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作者：
Y. Min;Minkyung Kim;Geon‐Tae Hwang;C. Ahn;Jong‐Jin Choi;B. Hahn;W. Yoon;G. Moon;Chee-Sung Park-Chee-Sun
本研究提出了一种合理的控制空位和载流子浓度的方法，在岩盐结构的IV-VI中引入V-VI硫化物，其中V、IV和空位占据阳离子位置，而VI占据阴离子位置。在概念验证实验中，Sb2Te3被引入到SNTE基质中，导致在晶体中形成空位(-SnxSb2Tex+3，其中-是空位)和致密的位错，同时优化了p型载流子浓度。与简单的Sb掺杂Sn1-xSbxTe样品不同，本研究中的-SnxSb2Tex+3样品在类似的载流子浓度水平下表现出更低的晶格热导率和更高的功率因数。具体来说，-Sn10Sb2Te13样品的晶格热导率接近SNTE(非晶态极限)的理论值，这是由于空位聚集形成的致密位错附近的大质量差异和局域应变引起的强声子散射，以及部分来自Sb的散射所致。这种简单的方法通过使用高成本、有害的掺杂剂，无需任何复杂的操作即可提高SNTE的热电性能。
This study proposes a rational approach for controlling vacancy and carrier concentrations simultaneously by introducing V-VI chalcogenide into rock-salt structured IV-VI, where V, IV, and vacancy occupy the cationic sites, and VI occupies the anionic sites. For proof-of-concept experiments, Sb2Te3is introduced in SnTe matrix, leading to the formation of vacancies (□SnxSb2Tex+3, where □ is vacancy) and dense dislocations in grains, along with an optimization of p-type carrier concentrations. Unlike simple Sb-doped Sn1-xSbxTe samples, the □SnxSb2Tex+3samples in this study show a much lower lattice thermal conductivity and an enhanced power factor at a similar carrier concentration level. Specifically, the lattice thermal conductivity of □Sn10Sb2Te13sample approaches the theoretical value of SnTe (amorphous limit) due to the strong phonon scattering caused by the large difference in mass and local strain near the dense dislocations formed from the clustering of vacancies and partly from the scattering from Sb. Such simple approach leads to boosting the thermoelectric performance of SnTe without any complex manipulations by using high-cost, harmful dopants.