Analysis and Implications of Structural Complexity in Low Lattice Thermal Conductivity High Thermoelectric Performance PbTe-PbSnS2 Composites

Chrysoula Ioannidou, Christos B. Lioutas, Nikolaos Frangis, Steven N. Girard, Mercouri G Kanatzidis

Research output: Contribution to journalArticle

Abstract

The high-performance PbTe-SnTe-PbS thermoelectric system forms a completely new composite PbTe-PbSnS2 with high n-type figure of merit. Electron diffraction and high-resolution electron microscopy characterization of the thermoelectric composite PbTe + 25% PbSnS2 reveals that the system is nanostructured, with PbSnS2nanocrystals in the range of 80 to 500 nm in size. In most of the cases, they are endotaxially grown within the PbTe matrix. Three independent crystal superstructures were observed for the PbSnS2 inclusions, originating from the same parent SnS-type structure. The presence of the parent structure is not excluded. Modified structural models for two of the superstructures observed in the PbSnS2 precipitates are proposed. Often, more than one of the structural phases are observed in the same nanocrystal, providing one extra phonon scattering factor in the system. Evidence was also found for the growth process of the nanocrystals, starting from PbS and followed by gradual dissolving of SnS. Our findings suggest that this nanostructured thermoelectric composite exhibits unique structural complexity, which contributes to the low lattice thermal conductivity reported for these nanocomposite materials.

Original languageEnglish
Pages (from-to)3771-3777
Number of pages7
JournalChemistry of Materials
Volume28
Issue number11
DOIs
Publication statusPublished - Jun 14 2016

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ASJC Scopus subject areas

  • Materials Chemistry
  • Chemical Engineering(all)
  • Chemistry(all)

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