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Anion-site-modulated thermoelectric properties in Ge2Sb2Te5-based compounds
Rare Metals ( IF 8.8 ) Pub Date : 2020-07-01 , DOI: 10.1007/s12598-020-01476-4
Ping Hu , Tian-Ran Wei , Shao-Ji Huang , Xu-Gui Xia , Peng-Fei Qiu , Jiong Yang , Li-Dong Chen , Xun Shi

The amalgamation of multi-subjects often elicits novel materials, new concepts and unexpected applications. Recently, Ge2Sb2Te5, as the most established phase-change material, has been found to exhibit decent thermoelectric performance in its stable, hexagonal phase. The challenge for higher figure of merit (zT) values lies in reducing the hole carrier concentration and enhancing the Seebeck coefficient, which, however, can be hardly realized by conventional doping. Here in this work, we report that the electrical properties of Ge2Sb2Te5 can be readily optimized by anion-site modulation. Specifically, Se/S substitution for Te induces stronger and more ionic bonding, lowering the hole density. Furthermore, an increase in electronic density of state is introduced by Se substitution, contributing to a large increase in Seebeck coefficient. Combined with the reduced thermal conductivity, maximum zT values above 0.7 at 800 K have been achieved in Se/S-alloyed materials, which is ~ 30% higher than that in the pristine Ge2Sb2Te5.

中文翻译:

Ge2Sb2Te5 基化合物中阴离子位点调制的热电特性

多学科的融合往往会引发新材料、新概念和意想不到的应用。最近,人们发现 Ge2Sb2Te5 作为最成熟的相变材料,在其稳定的六方相中表现出不错的热电性能。获得更高品质因数 (zT) 值的挑战在于降低空穴载流子浓度和提高塞贝克系数,然而,传统掺杂很难实现这一点。在这项工作中,我们报告称 Ge2Sb2Te5 的电性能可以通过阴离子位点调制轻松优化。具体而言,Se/S 取代 Te 会产生更强和更多的离子键,从而降低空穴密度。此外,Se 取代引入了电子态密度的增加,导致塞贝克系数的大幅增加。
更新日期:2020-07-01
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