Achieving zT > 2 in p-Type AgSbTe2− xSex Alloys via Exploring the Extra Light Valence Band and Introducing Dense Stacking Faults

Min Hong, Zhi Gang Chen, Lei Yang, Zhi Ming Liao, Yi Chao Zou, Yan Hui Chen, Syo Matsumura, Jin Zou

Research output: Contribution to journalArticle

51 Citations (Scopus)

Abstract

Through simultaneously enhancing the power factor by engineering the extra light band and enhancing phonon scatterings by introducing a high density of stacking faults, a record figure-of-merit over 2.0 is achieved in p-type AgSbTe2− xSex alloys. Density functional theory calculations confirm the presence of the light valence band with large degeneracy in AgSbTe2, and that alloying with Se decreases the energy offset between the light valence band and the valence band maximum. Therefore, a significantly enhanced power factor is realized in p-type AgSbTe2− xSex alloys. In addition, transmission electron microscopy studies indicate the appearance of stacking faults and grain boundaries, which together with grain boundaries and point defects significantly strengthen phonon scatterings, leading to an ultralow thermal conductivity. The synergetic strategy of simultaneously enhancing power factor and strengthening phonon scattering developed in this study opens up a robust pathway to tailor thermoelectric performance.

Original languageEnglish
Article number1702333
JournalAdvanced Energy Materials
Volume8
Issue number9
DOIs
Publication statusPublished - Mar 26 2018

All Science Journal Classification (ASJC) codes

  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)

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