Enhancing the thermoelectric properties of p-type bulk Bi-Sb-Te nanocomposites via solution-based metal nanoparticle decoration

Sungwoo Hwang, Sang Il Kim, Kyunghan Ahn, Jong Wook Roh, Dae Jin Yang, Sang Mock Lee, Kyu Hyoung Lee

Research output: Contribution to journalArticlepeer-review

33 Scopus citations

Abstract

Embedding nanosized particles in bulk thermoelectric materials is expected to lower the lattice thermal conductivity by enhancing the degree of interface phonon scattering, thus improving their thermoelectric figure of merit ZT. We have developed a wet chemical process to fabricate Bi0.5Sb 1.5Te3-based thermoelectric nanocomposites which include nanometer-sized metal particles. By simple solution mixing of metal acetate precursors and Bi0.5Sb1.5Te3 powders in ethyl acetate as a medium for homogeneous incorporation, it is possible to apply various types of metal nanoparticles onto the surfaces of the thermoelectric powders. Next, bulk Bi0.5Sb1.5Te3 nanocomposites with homogeneously dispersed metal nanoparticles were fabricated using a spark plasma sintering technique. The lattice thermal conductivities were reduced by increasing the long-wavelength phonon scattering in the presence of metal nanoparticles, while the Seebeck coefficients increased for a few selected metal-decorated nanocomposites, possibly due to the carrier-energy-filtering effect. Finally, the figure of merit ZT was enhanced to 1.4 near room temperature. This approach highlights the feasibility of incorporating various types of nanoparticles into an alloy matrix starting by wet chemical routes, which is an effective means of improving the thermoelectric performance of Bi-Te-based alloys.

Original languageEnglish
Pages (from-to)1411-1416
Number of pages6
JournalJournal of Electronic Materials
Volume42
Issue number7
DOIs
StatePublished - Jul 2013

Keywords

  • BiSbTe
  • carrier filtering effect
  • Metal nanoparticle decoration
  • spark plasma sintering
  • thermoelectric nanocomposite

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