Seeing is believing: Weak phonon scattering from nanostructures in alkali metal-doped lead telluride

Jiaqing He*, John Androulakis, Mercouri G. Kanatzidis, Vinayak P. Dravid

*Corresponding author for this work

Research output: Contribution to journalArticle

73 Scopus citations

Abstract

Alkali metal doped p-type PbTe is a canonical thermoelectric material studied extensively for heat-to-power generation at high temperature. Most reports have indirectly indicated alkali metals to be conventional with PbTe forming homogeneous solid solutions. Using transmission electron microscopy (TEM), we show the presence of platelet-like nanostructures in these systems containing Na and/or K. By combining further TEM and semiclassical theoretical calculations based on a modified Debye model of the lattice thermal conductivity, we explain the lack of efficacy of these nanostructures for strong phonon scattering. These findings are important in the understanding of alkali metals as carriers in p-type lead chalcogenides. These results also underscore that not all nanostructures favorably scatter phonons in a matrix; an insight that may help in further improvements of the power factor and the overall figure of merit.

Original languageEnglish (US)
Pages (from-to)343-347
Number of pages5
JournalNano letters
Volume12
Issue number1
DOIs
StatePublished - Jan 11 2012

Keywords

  • Thermoelectric materials
  • lattice thermal conductivity
  • nanostructures
  • phonon scattering
  • transmission electron microscopy

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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