Substantial thermoelectric enhancement achieved by manipulating the band structure and dislocations in Ag and La co-doped SnTe

• 作者: Wenjing XU Zhongwei ZHANG Chengyan LIU Jie GAO Zhenyuan YE Chunguang CHEN Ying PENG Xiaobo BAI Lei MIAO
• 来源期刊: 先进陶瓷（英文版）
• 年，卷（期）: 2021,（4）
• 所属期刊栏目: Research Article
• 页码范围: 860-870
• 页数: 11页
• 语种: 英文

摘要

Eco-friendly SnTe based thermoelectric materials are intensively studied recently as candidates to replace PbTe;yet the thermoelectric performance of SnTe is suppressed by its intrinsically high carrier concentration and high thermal conductivity.In this work,we confirm that the Ag and La co-doping can be applied to simultaneously enhance the power factor and reduce the thermal conductivity,contributing to a final promotion of figure of merit.On one hand,the carrier concentration and band offset between valence bands are concurrently reduced,promoting the power factor to a highest value of～2436 μW·m-1·K-2 at 873 K.On the other hand,lots of dislocations(～3.16×107 mm-2) associated with impurity precipitates are generated,resulting in the decline of thermal conductivity to a minimum value of 1.87 W·m-1·K-1 at 873 K.As a result,a substantial thermoelectric performance enhancement up to zT ≈ 1.0 at 873 K is obtained for the sample Sn0.94Ag0.09La0.05Te,which is twice that of the pristine SnTe (zT ≈ 0.49 at 873 K).This strategy of synergistic manipulation of electronic band and microstructures via introducing rare earth elements could be applied to other systems to improve thermoelectric performance.