Synergistic modulation of power factor and thermal conductivity in Cu3SbSe4 towards high thermoelectric performance

In this study, we develop a synergistic modulation of the thermal conductivity and power factor of Cu3SbSe4-based materials through Sn and Zr or Hf co-doping by using a facile microwave-assisted solvothermal method. A series of Cu3Sb1-xMxSe4 (M = Zr or Hf, x = 0, 0.02, 0.04, 0.06 and 0.08) compounds are firstly synthesized through the microwave-assisted solvothermal method combined with spark plasma sintering (SPS) process. The effect of Zr and Hf doping on the thermoelectric properties of Cu3Sb1-xMxSe4 (M = Zr or Hf) has been investigated. With increasing the content of Hf and Zr, the thermal conductivity of Cu3Sb1-xMxSe4 (M = Zr or Hf) is obviously decreased to 0.518 Wm(-1)K(-1) of Cu3Sb0.92Hf0.08Se4 and 0.433 Wm(-1)K(-1) of Cu3Sb0.92Zr0.08Se4 at 623 K, respectively. In addition, Sn doping further improves the low electrical conductivity and boosts the power factor, yielding a peak zT value of similar to 0.82 of Cu3Sb0.91Sn0.03Hf0.06Se4 at 623 K, which is similar to 228% higher than that of the pristine Cu3SbSe4. Our work provides a new methodology for the decoupling of thermal and electrical properties of the Cu3SbSe4-based thermoelectric materials.