Enhanced thermoelectric performance of CuSbSe2 via Mn doping

Abstract

Ternary chalcostibite CuSbSe2 compound is known for low thermal conductivity. However, the poor electrical properties severely limit its thermoelectric performance. In this study, the Mn-doped CuSb1-xMnxSe2 (x = 0–0.04) samples were synthesized by vacuum melting with spark plasma sintering, and their thermoelectric properties were characterized. The results indicate that the impurity phase Cu3SbSe3 will be generated when Mn content x > 0.02, and the carrier concentration and mobility were optimized significantly for the Mn-doped compounds, thus enhancing the electrical transport performance. In terms of results, the PF increases from 1.3 × 102 to 2.18 × 102 µW m−1 K−2 at 673 K. Point defects and the second phase enhance phonon scattering and lead to a lower lattice thermal conductivity for CuSb1-xMnxSe2 compounds, the κl decreases from 0.39 to 0.26 W m−1 K−1 at 673 K. As a consequence, a maximum figure of merit ZT of ∼0.53 was achieved at 673 K for CuSb0.97Mn0.03Se2, which is 140 % higher than the intrinsic CuSbSe2.