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

Wenjing Xu, Zhongwei Zhang, Chengyan Liu, Jie Gao, Zhenyuan Ye, Chunguang Chen, Ying Peng, Xiaobo Bai, Lei Miao

Research output: Contribution to journalArticlepeer-review

Abstract

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.

Original languageEnglish
JournalJournal of Advanced Ceramics
DOIs
Publication statusAccepted/In press - 2021

Keywords

  • Ag and La co-doping
  • SnTe
  • band convergence
  • dislocation
  • thermoelectric performance

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites

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