Defect-Controlled Electronic Structure and Phase Stability in Thermoelectric Skutterudite CoSb3

Guodong Li, Umut Aydemir, Max Wood, William A. Goddard, Pengcheng Zhai, Qingjie Zhang*, G. Jeffrey Snyder

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

Controlling extrinsic defects to tune the carrier concentration of electrons or holes is a crucial point with regard to the engineering application of thermoelectric semiconductors. To understand the defect-controlled electronic structure in thermoelectric materials, we apply density functional theory (DFT) to investigate the defect chemistry of dopants M (M = O, S, Se, or Te) in CoSb3. DFT predicts that the breakage of Sb4 rings induced by these dopants produces the unexpected (n- or p-type) conductivity behavior in CoSb3. For example, energetically dominant O interstitials (Oi) chemically break Sb4 rings and form O-4Sb five-membered rings, leading to the charge neutral behavior of Oi. While S interstitials (Si) collapse Te-3Sb four-membered rings within Te doped CoSb3 leading to p-type conduction behavior, Se substitution on Sb (SeSb) breaks the Se-Te-2Sb four-membered ring, resulting in a charge neutral behavior of the SeSb+TeSb complex defect. Furthermore, the solubility limits of M dopants (M = S, Se, or Te) are also calculated to provide essential information about single-phase material design. This study provides new insight into understanding the complicated chemical structure in doped CoSb3, which is beneficial for devising effective doping strategies for the development of high-performance bulk thermoelectric materials.

Original languageEnglish (US)
Pages (from-to)3999-4007
Number of pages9
JournalChemistry of Materials
Volume29
Issue number9
DOIs
StatePublished - May 9 2017

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

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