Improvement in thermoelectric properties of Se-free Cu3SbS4 compound

TitleImprovement in thermoelectric properties of Se-free Cu3SbS4 compound
Publication TypeConference Paper
Year of Publication2013
AuthorsSuzumura A, et. al.
Conference NameProceedings on the 32rd International Conference on Thermoelectrics, ICT2013
Conference Start Date30/06/2013
PublisherJournal of Electronic Materials
Conference LocationKobe, Japan
Keywords[Swiss Award]

Recently, Cu-based chalcogenides such as Cu3SbSe4, Cu2Se, and Cu2SnSe3 have attracted much attention because of their high thermoelectric performance and their common feature of very low thermal conductivity. However, for practical use, materials without toxic elements such as selenium are preferable. In this paper, we report Se-free Cu3SbS4 thermoelectric material and improvement of its figure of merit (ZT) by chemical substitutions. Substitutions of 3 at.% Ag for Cu and 2 at.% Ge for Sb lead to significant reductions in the thermal conductivity by 37% and 22%, respectively. These substitutions do not sacrifice the power factor, thus resulting in enhancement of the ZTvalue. The sensitivity of the thermal conductivity to chemical substitutions in these compounds is discussed in terms of the calculated phonon dispersion and previously proposed models for Cu-based chalcogenides. To improve the power factor, we optimize the hole carrier concentration by substitution of Ge for Sb, achieving a power factor of 16 μW/cm K2 at 573 K, which is better than the best reported for Se-based Cu3SbSe4 compounds.