兴奋剂
材料科学
掺杂剂
热电效应
钇
电阻率和电导率
热电材料
光电子学
塞贝克系数
空位缺陷
热导率
纳米技术
凝聚态物理
冶金
电气工程
热力学
复合材料
物理
工程类
氧化物
作者
Weihong Gao,Zihang Liu,Wenhao Zhang,Naoki Sato,Quansheng Guo,Takao Mori
摘要
Optimization of the carrier concentration by doping/alloying is a key prerequisite for improving thermoelectric performance. In reality, it is, however, challenging to identify effective dopants in some specific systems. Herein, we discovered that Y doping significantly reduced the carrier concentration, enhanced the power factor, and, therefore, boosted thermoelectric performance. The high Y-doping efficiency had origin in the fact that the compensating effect due to Ge vacancies was weaker in comparison to other dopants in GeTe because the slightly increased rhombohedral interaxial angle suggested that the Ge-vacancy concentration would not be altered dramatically. In addition, first-principles calculations revealed that Y doping did not induce significant modifications on the band structure, consistent with electrical transport measurement results. Moreover, Bi doping was found to be more powerful than Sb doping to further increase electrical resistivity and to enhance performance in which the highest peak ZT ∼ 1.8 together with a high average ZT ∼ 1.1 from 300 K to 723 K was achieved. Our work not only highlighted the efficacy of Y doping in enhancing the thermoelectric performance of the GeTe system but also developed advanced GeTe-based materials for power generation applications.
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