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Significantly Enhanced Thermoelectric Performance Achieved in CuGaTe2 through Dual-Element Permutations at Cation Sites
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2022-06-22 , DOI: 10.1021/acsami.2c07557
Mengyue Wu 1 , Lujun Zhu 2 , Shixuan Liu 3 , Mingzhen Song 1 , Fudong Zhang 1 , Pengfei Liang 2 , Xiaolian Chao 1 , Zupei Yang 1 , Jiaqing He 3 , Di Wu 1
Affiliation  

CuGaTe2 has become a widely studied mid-temperature thermoelectric material due to the advantages of large element abundance, proper band gap, and intrinsically high Seebeck coefficient. However, the intrinsically high lattice thermal conductivity and low room-temperature electrical conductivity result in a merely moderate thermoelectric performance for pristine CuGaTe2. In this work, we found that Cu deficiency can significantly reduce the activation energy Ea of Cu vacancies from ∼0.17 eV for pristine CuGaTe2 to nearly zero for Cu0.97GaTe2, thus leading to dramatic improvements in hole concentration and power factor. More remarkably, element permutations (Ag/Cu and In/Ga) at both cation sites can effectively reduce the lattice thermal conductivity at the entire testing temperatures by producing intensive atomic-scale mass and strain fluctuations. Eventually, an ultrahigh peak ZTmax value of ∼1.5 at 873 K is achieved in the composition of Cu0.72Ag0.25Ga0.6In0.4Te2, while a large average ZTavg value of ∼0.7 (323–873 K) is obtained in the Cu0.67Ag0.3Ga0.6In0.4Te2 sample, both of which are significant improvements over pristine CuGaTe2.

中文翻译:

通过阳离子位点的双元素排列显着增强 CuGaTe2 的热电性能

CuGaTe 2具有元素丰度大、带隙合适和固有的高塞贝克系数等优点,已成为一种被广泛研究的中温热电材料。然而,固有的高晶格热导率和低室温电导率导致原始CuGaTe 2的热电性能仅适中。在这项工作中,我们发现Cu 缺乏可以显着降低Cu 空位的活化能E a从原始CuGaTe 2 的~0.17 eV 降低到Cu 0.97 GaTe 2的几乎为零,从而导致空穴浓度和功率因数的显着提高。更显着的是,两个阳离子位点的元素排列(Ag/Cu 和 In/Ga)可以通过产生强烈的原子级质量和应变波动有效地降低整个测试温度下的晶格热导率。最终,在 Cu 0.72 Ag 0.25 Ga 0.6 In 0.4 Te 2的组成中,在 873 K 处实现了约 1.5的超高峰值ZT最大值而在Cu 0.67 Ag 0.3 Ga 0.6 In 0.4 Te2样品,这两者都是对原始 CuGaTe 2的显着改进。
更新日期:2022-06-22
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