Band flattening and phonon-defect scattering in cubic SnSe-AgSbTe2 alloy for thermoelectric enhancement
Band flattening and phonon-defect scattering in cubic SnSe-AgSbTe2 alloy for thermoelectric enhancement
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用于热电增强的立方 SnSe-AgSbTe2 合金中的能带平坦化和声子缺陷散射
DOI：
10.1016/j.mtphys.2020.100298
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Jun Jiang
中科院分区：
文献类型：
--
作者：
Hongxiang Wang;Haoyang Hu;Na Man;Chenglong Xiong;Yukun Xiao;Xiaojian Tan;Guoqiang Liu;Jun Jiang
岩盐型SnSe具有多能带谷和低热导率的特性，是一种很有潜力的热电材料。在此，我们制备了立方SnSe-AgSbTe 2合金，并展示了协同优化的电子和热输运性质。对于前者，AgSbTe 2合金化可以调整费米面，促进能带平坦化，同时提高态密度、有效质量和载流子浓度。对于后者，AgSbTe 2合金化引起的声子-缺陷散射导致晶格热导率的大幅降低。在820 K时，Sn_（0.5）Ag_（0.25）Sb_（0.25）Se_（0.5）Te_（0.5）的ZTmax为1.00，ZTave为0.70（300-820 K）。AgSbTe 2合金化还可以提高材料的力学性能，其维氏硬度达到1.90 Gpa，比纯SnSe提高了4倍多。
With multiple band valleys and intrinsic low thermal conductivity, rock-salt SnSe possesses great potential as a promising thermoelectric material. Herein, we prepare cubic SnSe–AgSbTe2alloy and demonstrate the synergistically optimized electronic and thermal transport properties. For the former, AgSbTe2alloying can tune the Fermi surface and promote the band flattening, concurrently improving the density of state effective mass and carrier concentration. For the latter, the strong phonon-defect scattering caused by AgSbTe2alloying contributes to a great reduction of lattice thermal conductivity. Collectively, an obviously enhancedZTmaxof 1.00 at 820 K andZTaveof 0.70 (300–820 K) are achieved in Sn0.5Ag0.25Sb0.25Se0.5Te0.5. Moreover, AgSbTe2alloying can also improve the mechanical property and the Vickers hardness reaches 1.90 Gpa, which is over four times higher than that of pristine SnSe.