Reduced thermal conductivity in Pb-alloyed AgSbTe 2 thermoelectric materials

Hsin-Jay Wu, Sinn Wen Chen*, Teruyuki Ikeda, G. Jeffrey Snyder

*Corresponding author for this work

Research output: Contribution to journalArticle

25 Scopus citations

Abstract

Pb-alloyed AgSbTe 2 (Pb xAg 20Sb 30-xTe 50 (x = 3, 4, 5 and 6)) composites were synthesized using a modified Bridgman method with a graphite mold to form plate-like samples. The Bridgman-grown specimens were dense, with few solidification cavities, and were sufficiently mechanically robust for a variety of electronic/thermal transport measurements. Inhomogeneity was found on the grain boundary, and was embedded with the nanoprecipitates of δ-Sb 2Te with a feature size of 100 nm of the 5 at.% Pb and 6 at.% Pb specimens. A combined effect of alloying, inhomogeneity and nanoprecipitates leads to a low thermal conductivity of 0.3-0.4 W m -1 K -1, which approaches the theoretical minimum thermal conductivity of the amorphous material (κ min ∼ 0.36 W m -1 K -1). A peak of the zT value, ranging from 0.7 to 0.8, is achieved at 425 K. Further annealing at 673 K increases the grain size and causes a reduction in the value of the zT peak to 0.4.

Original languageEnglish
Pages (from-to)6144-6151
Number of pages8
JournalActa Materialia
Volume60
Issue number17
DOIs
StatePublished - 1 Oct 2012

Keywords

  • AgSbTe
  • Bridgman
  • Nanoprecipitate
  • Thermal conductivity
  • Thermoelectric

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