Synergistic Effect of Chemical Substitution and Insertion on the Thermoelectric Performance of Cu26V2Ge6S32Colusite

Yuta Shimizu, Koichiro Suekuni, Hikaru Saito, Pierric Lemoine, Emmanuel Guilmeau, Bernard Raveau, Raju Chetty, Michihiro Ohta, Toshiro Takabatake, Michitaka Ohtaki

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


Copper-based sulfides are promising materials for thermoelectric applications, which can convert waste heat into electricity. This study reports the enhanced thermoelectric performance of Cu26V2Ge6S32 colusite via substitution of antimony (Sb) for germanium (Ge) and introduction of copper (Cu) as an interstitial atom. The crystal structure of the solid solutions and Cu-rich compounds were analyzed by powder X-ray diffraction and scanning transmission electron microscopy. Both chemical approaches decrease the hole carrier concentration, which leads to a reduction in the electronic thermal conductivity while keeping the thermoelectric power factor at a high value. Furthermore, the interstitial Cu atoms act as phonon scatterers, thereby decreasing the lattice thermal conductivity. The combined effects increase the dimensionless thermoelectric figure of merit ZT from 0.3 (Cu26V2Ge6S32) to 0.8 (Cu29V2Ge5SbS32) at 673 K.

Original languageEnglish
Pages (from-to)11364-11373
Number of pages10
JournalInorganic chemistry
Issue number15
Publication statusPublished - Aug 2 2021

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry


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