[24p-E205-1~18] 9.4 Thermoelectric conversion

△ [24p-E205-9] Crystal structure analysis and carrier concentration tuning of a novel Cu–S-based thermoelectric semiconductor Cu₇VSnS₈

〇(M1)Shuya Kozai¹, Koichiro Suekuni¹, Eiji Nishibori², Philipp Sauerschnig³, Michihiro Ohta³, Michitaka Ohtaki¹ (1.Kyushu Univ., 2.Univ. of Tsukuba, 3.AIST GZR)

Keywords:thermoelectric materials, sulfides, semiconductor

We report the crystal structure and thermoelectric properties of a novel Cu–S-based semiconductor Cu₇VSnS₈. X-ray diffraction analysis revealed that Cu₇VSnS₈ crystallizes in a tetragonal structure similar to that for the mawsonite Cu₆Fe₂SnS₈. Cu₇VSnS₈ showed semiconducting properties and low thermal conductivity (0.5 W K⁻¹ m⁻¹ at 673 K). The substitution of Ti for V as Cu₇Ti_xV_1−xSnS₈ (x = 0.25, 0.5, 0.75) increased the hole carrier concentration, leading to an enhanced thermoelectric power factor and dimensionless figure of merit ZT (0.6–0.7 at 673 K).