High Thermoelectric Performance and Enhanced Mechanical Stability of p-type Ge1-xSbxTe
High Thermoelectric Performance and Enhanced Mechanical Stability of p-type Ge1-xSbxTe
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DOI：
10.1021/acs.chemmater.5b03434
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发表时间：
2015-10-27
影响因子：
8.6
通讯作者：
Biswas, Kanishka
中科院分区：
文献类型：
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作者：
Perunnal, Suresh;Roychowdhury, Subhajit;Biswas, Kanishka
通过同时提高Seebeck系数和降低热导率，实现了无Pb p型Ge 1-xSbxTe样品在725 K沿着接近1.85的热电优值zT和显著的循环温度稳定性。由于Sb的施主掺杂性质，GeTe中的Sb掺杂降低了载流子浓度，并且通过增加样品的立方性质来增强价带简并，这共同提高了300-773 K温度范围内的塞贝克系数。显着的热导率降低是由于集体声子散射从各种台面结构的域变体，孪晶和反转边界，纳米结构的缺陷层，和固溶点缺陷。高性能的Ge0.9Sb0.1Te样品显示出类似于206 Hv的机械稳定性（维氏显微硬度），这与其他流行的热电材料（例如Bi 2 Te 3、PbTe、PbSe、Cu 2Se和TAGS）相比显著更高。
High thermoelectric figure of merit, zT, of similar to 1.85 at 725 K along with significant cydable temperature stability was achieved in Pb-free p-type Ge1-xSbxTe samples through simultaneous enhancement in Seebeck coefficient and reduction of thermal conductivity. Sb doping in GeTe decreases the carrier concentration due to the donor dopant nature of Sb and enhances the valence band degeneracy by increasing the cubic nature of the sample, which collectively boost Seebeck coefficient in the temperature range of 300-773 K. Significant thermal conductivity reduction was achieved due to collective phonon scattering from various mesa-structured domain variants, twin and inversion boundaries, nanostructured defect layers, and solid solution point defects. The high performance Ge0.9Sb0.1Te sample shows mechanical stability (Vickers microhardness) of similar to 206 Hv, which is significantly higher compared to other popular thermoelectric materials such as Bi2Te3, PbTe, PbSe, Cu2Se, and TAGS.