Kim Minyoung, Kim Sang-Il, Kim Sung Wng, Kim Hyun-Sik, Lee Kyu Hyoung
Department of Materials Science and Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, South Korea.
Department of Materials Science and Engineering, University of Seoul, 163 Seoulsiripdae-ro, Dongdaemun-gu, Seoul, 02504, South Korea.
Adv Mater. 2021 Nov;33(47):e2005931. doi: 10.1002/adma.202005931. Epub 2021 Mar 24.
Thermoelectrics, which can generate electricity from a temperature difference, or vice versa, is a key technology for solid-state cooling and energy harvesting; however, its applications are constrained owing to low efficiency. Since the conversion efficiency of thermoelectric devices is directly obtained via a figure of merit of materials, zT, which is related to the electronic and thermal transport characteristics, the aim here is to elucidate physical parameters that should be considered to understand transport phenomena in semiconducting materials. It is found that the weighted mobility ratio of the majority and minority carrier bands is an important parameter that determines zT. For nanograined Bi-Sb-Te alloy, the unremarked role of this parameter on temperature-dependent electronic transport properties is demonstrated. This analysis shows that the control of the weighted mobility ratio is a promising way to enhance zT of narrow bandgap thermoelectric materials.
热电学能够利用温差发电，反之亦然，是固态冷却和能量收集的关键技术；然而，由于效率低下，其应用受到限制。由于热电器件的转换效率直接通过材料的品质因数zT获得，zT与电子和热传输特性相关，因此这里的目的是阐明理解半导体材料中传输现象时应考虑的物理参数。研究发现，多数载流子带和少数载流子带的加权迁移率比是决定zT的一个重要参数。对于纳米晶Bi-Sb-Te合金，该参数对温度依赖的电子传输特性的作用未被注意到。该分析表明，控制加权迁移率比是提高窄带隙热电材料zT的一种有前途的方法。
