Phase separation and interface effect in pseudo-quaternary composites of AgxBi0.5Sb1.5−xTe3−x

Yoo Jang Song, R. Lydia, Chan Chieh Lin, Jong Soo Rhyee, J. Chung, Oh Myoung Kwon, Su Dong Park, Bong Seo Kim

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

We investigated anisotropic thermoelectric properties of p-type AgxBi0.5Sb1.5−xTe3−x (x= 0.0, 0.1, 0.2 and 0.3) compounds, prepared by melting and hot press sintering. During hot press sintering and annealing process, the eutectoid decomposition of Ag2Te from (Bi,Sb)2Te3 matrix induces intrinsic thermoelectric composites Ag2+δTe/(Bi,Sb)2Te3. The phase separation increases the phonon scattering which lowered the lattice thermal conductivity. We also found the metallic interfacial layer in a grain boundary from the measurements of conducting atomic force microscopy (AFM) and scanning Seebeck- and scanning thermal-microscopy (SThM). Here we argue that the interfacial conductivity attributes to the increase of power factor due to increase of mobility. Thereby, the phase separation of Ag2Te from the (Bi,Sb)2Te3 matrix gives rise to the enhanced thermoelectric properties at mild-temperature range, resulting in the enhancement of dimensionless thermoelectric figure-of-merit ZT value of 1.02 at 567 K for x= 0.1 along the vertical direction.

Original languageEnglish
Pages (from-to)1018-1025
Number of pages8
JournalJournal of Alloys and Compounds
Volume708
DOIs
Publication statusPublished - 2017 Jun 25

Keywords

  • (Bi,Sb)Te
  • AgTe
  • Interface
  • Phase separation
  • Thermoelectric

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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