Ultra-low thermal conductivity and high thermoelectric performance realized in a Cu3SbSe4 based system

Cu3SbSe4-Based materials were fabricated through Sn-doping and AgSb0.98Ge0.02Se2 incorporation and their thermoelectric properties were investigated in the temperature range from 300 K to 675 K. A remarkable enhancement in thermoelectric performance was obtained, which can be ascribed to the synergistic adjustment of electrical and thermal transport. The introduction of AgSb0.98Ge0.02Se2 nanoparticles strengthened phonon scattering in the composites, resulting in a low thermal conductivity. Simultaneously, a high power factor was maintained. As a result, a maximum figure of merit of 1.23 was obtained at 675 K for the sample Cu3Sb0.96Sn0.04Se4–3 wt% AgSb0.98Ge0.02Se2, which is one of the highest values ever reported in the Cu3SbSe4-based system.