Lattice Dislocations Enhancing Thermoelectric PbTe in Addition to Band Convergence

Zhiwei Chen, Zhengzhong Jian, Wen Li, Yunjie Chang, Binghui Ge, Riley Hanus, Jiong Yang, Yue Chen, Mingxin Huang, Gerald Jeffrey Snyder, Yanzhong Pei*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

292 Scopus citations

Abstract

Phonon scattering by nanostructures and point defects has become the primary strategy for minimizing the lattice thermal conductivity (κL) in thermoelectric materials. However, these scatterers are only effective at the extremes of the phonon spectrum. Recently, it has been demonstrated that dislocations are effective at scattering the remaining mid-frequency phonons as well. In this work, by varying the concentration of Na in Pb0.97Eu0.03Te, it has been determined that the dominant microstructural features are point defects, lattice dislocations, and nanostructure interfaces. This study reveals that dense lattice dislocations (≈4 × 1012 cm−2) are particularly effective at reducing κL. When the dislocation concentration is maximized, one of the lowest κL values reported for PbTe is achieved. Furthermore, due to the band convergence of the alloyed 3% mol. EuTe the electronic performance is enhanced, and a high thermoelectric figure of merit, zT, of ≈2.2 is achieved. This work not only demonstrates the effectiveness of dense lattice dislocations as a means of lowering κL, but also the importance of engineering both thermal and electronic transport simultaneously when designing high-performance thermoelectrics.

Original languageEnglish (US)
Article number1606768
JournalAdvanced Materials
Volume29
Issue number23
DOIs
StatePublished - Jun 20 2017

Keywords

  • band convergence
  • lattice dislocations
  • lattice thermal conductivity
  • thermoelectrics

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

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