Wu Mengyue, Zhu Lujun, Liu Shixuan, Song Mingzhen, Zhang Fudong, Liang Pengfei, Chao Xiaolian, Yang Zupei, He Jiaqing, Wu Di
Key Laboratory for Macromolecular Science of Shaanxi Province, School of Materials Science and Engineering, Shaanxi Normal University, Xi'an 710119, China.
School of Physics and Information Technology, Shaanxi Normal University, Xi'an 710119, China.
ACS Appl Mater Interfaces. 2022 Jul 6;14(26):30046-30055. doi: 10.1021/acsami.2c07557. Epub 2022 Jun 22.
CuGaTe 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 CuGaTe. In this work, we found that Cu deficiency can significantly reduce the activation energy of Cu vacancies from ∼0.17 eV for pristine CuGaTe to nearly zero for CuGaTe, 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 value of ∼1.5 at 873 K is achieved in the composition of CuAgGaInTe, while a large average value of ∼0.7 (323-873 K) is obtained in the CuAgGaInTe sample, both of which are significant improvements over pristine CuGaTe.
由于元素丰度高、带隙合适以及本征塞贝克系数高，铜镓碲已成为一种被广泛研究的中温热电材料。然而，本征晶格热导率高和室温电导率低导致原始铜镓碲的热电性能仅处于中等水平。在这项工作中，我们发现铜缺陷可将铜空位的激活能从原始铜镓碲的约0.17电子伏特显著降低至铜镓碲的近零，从而导致空穴浓度和功率因数大幅提高。更值得注意的是，两个阳离子位点的元素置换（银/铜和铟/镓）可通过产生强烈的原子尺度质量和应变波动，在整个测试温度下有效降低晶格热导率。最终，在铜银镓铟碲组成中，873K时实现了约1.5的超高峰值，而在铜银镓铟碲样品中获得了约0.7的大平均值（323 - 873K），这两者相对于原始铜镓碲均有显著提升。
