High-Temperature Thermoelectric Properties of Cu₃In₅Te₉ with Defect-Chalcopyrite Structure

The relatively high-temperature thermoelectric (TE) figure of merit (ZT) of Cu₂In₄Te₇ with the defect zinc-blend structure has been reported recently. In this study, Cu₃In₅Te₉ which has the defect chalcopyrite structure was prepared, and the TE properties, i.e., electrical resistivity (ρ), Seebeck coefficient (S), and thermal conductivity (κ) were evaluated in the temperature range from room temperature to 700 K. At 700 K, the ρ, S, and κ were 19.7×10⁻⁵ Ωm, +264 μVK⁻¹, and 0.70 Wm⁻¹ K⁻¹, respectively, resulting in the maximum ZT = 0.35 at 700 K for Cu₃In₅Te₉, which was higher than that of Cu₂In₄Te₇.