Nanograined thermoelectric Bi2Te2.7Se0.3 with ultralow phonon transport prepared from chemically exfoliated nanoplatelets

Jieun Ko, Jong Young Kim, Soon Mok Choi, Young Soo Lim, Won Seon Seo, Kyu Hyoung Lee

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

Herein, we report on a scalable synthesis of surfactant-free Bi 2Te2.7Se0.3 nanocrystals by chemical exfoliation and subsequent spark plasma sintering to fabricate nanostructured thermoelectric bulk materials. The exfoliated n-type Bi2Te 2.7Se0.3 nanoplatelets were shown to transform into nanoscroll-type crystals (∼5 nm in diameter, ∼50 nm in length) by ultrasonication. The thermoelectric performance of the Bi2Te 2.7Se0.3 nanocrystals was found to be recoverable by minimizing surface oxides by chemical reduction of the exfoliated suspensions. Nanostructured bulk materials, composed of plate-like grains with ∼50 nm thickness, were prepared by sintering of the ultrasonicated sample using a spark plasma sintering technique. The resulting compound showed drastic reduction of lattice thermal conductivity (0.31 W m-1 K-1 @ 400 K) due to enhanced phonon scattering at highly dense grain boundaries without deterioration of the power factor (21.0 × 10-4 W m-1 K-2 @ 400 K). The peak ZT value of the present compound (∼0.8 @400 K) is comparable to that of n-type single crystalline Bi 2(Te,Se)3, which is one of the highest among the reported values for n-type materials synthesized by a soft chemical route.

Original languageEnglish
Pages (from-to)12791-12796
Number of pages6
JournalJournal of Materials Chemistry A
Volume1
Issue number41
DOIs
Publication statusPublished - 2013 Nov 7

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)

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