Carrier concentration tuning in thermoelectric thiospinel Cu2CoTi3S8 by oxidative extraction of copper

Katsuaki Hashikuni, Koichiro Suekuni, Kosuke Watanabe, Yohan Bouyrie, Michihiro Ohta, Michitaka Ohtaki, Toshiro Takabatake

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


We report a method for carrier concentration tuning in the thermoelectric thiospinel Cu2CoTi3S8, which exhibits an n-type metallic character and a high power factor. An oxidative Cu extraction treatment produced Cu defects, resulting in Cu2−xCoTi3S8 up to x = 0.62. The electron carrier concentration was effectively reduced by this treatment, leading to the decrease in power factor, whereas the electronic contribution to the thermal conductivity was suppressed. As a result, the dimensionless figure of merit ZT remained unchanged as 0.2 at 670 K in the whole range of x ≤ 0.62. The oxidative Cu extraction described in this paper offers an opportunity to tune the electron carrier concentration for Cu-containing thermoelectric materials.

Original languageEnglish
Pages (from-to)5-10
Number of pages6
JournalJournal of Solid State Chemistry
Publication statusPublished - Mar 2018

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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