Phonon scattering and thermal conductivity in p-type nanostructured PbTe-BaTe bulk thermoelectric materials

Shih Han Lo, Jiaqing He, Kanishka Biswas, Mercouri G Kanatzidis, Vinayak P. Dravid

Research output: Contribution to journalArticle

65 Citations (Scopus)

Abstract

Transmission electron microscopy studies show that a PbTe-BaTe bulk thermoelectric system represents the coexistence of solid solution and nanoscale BaTe precipitates. The observed significant reduction in the thermal conductivity is attributed to the enhanced phonon scattering by the combination of substitutional point defects in the solid solution and the presence of high spatial density of nanoscale precipitates. In order to differentiate the role of nanoscale precipitates and point defects in reducing lattice thermal conductivity, a modified Callaway model is proposed, which highlights the contribution of point defect scattering due to solid solution in addition to that of other relevant microstructural constituents. Calculations indicate that in addition to a 60% reduction in lattice thermal conductivity by nanostructures, point defects are responsible for about 20% more reduction and the remaining reduction is contributed by the collective of dislocation and strain scattering. These results underscore the need for tailoring integrated lengtha scales for enhanced heata carrying phonon scattering in high performance thermoelectrics.

Original languageEnglish
Pages (from-to)5175-5184
Number of pages10
JournalAdvanced Functional Materials
Volume22
Issue number24
DOIs
Publication statusPublished - Dec 19 2012

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Keywords

  • microstructures
  • thermal conductivity
  • thermoelectrics
  • transmission electron microscopy

ASJC Scopus subject areas

  • Biomaterials
  • Electrochemistry
  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

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