Improvement of thermoelectric properties of Cu 3 SbSe 4 hierarchical with in-situ second phase synthesized by microwave-assisted solvothermal method

Pb doped Cu 3 Sb 1-x Pb x Se 4 (x = 0, 0.01, 0.02, 0.04 and 0.06) compounds have been synthesized via microwave-assisted solvothermal method followed by SPS progress, and their thermoelectric properties from 300 K to 623 K has been explored. On one hand, Pb doping in the Sb site improved the electrical properties of Cu 3 SbSe 4, on the other hand, the second phase PbSe formed at the high doping content (x ≥ 0.02) reduced the thermal conductivity by the phonon scattering. Altogether, the improvement of the electrical properties and decrease of the thermal conductivity results in a promising peak zT of ∼0.52 at 623 K of Cu 3 Sb 0.96 Pb 0.04 Se 4 sample, which is about 80% higher than that of the un-doped Cu 3 SbSe 4. The current work provides a method which can reduce the thermal conductivity by forming heterojunction and also improve the electrical properties by doping of one element.