Effect of Pb Doping on the Thermoelectric Performance of Eco-Friendly Cu3SbS4

Abstract

Cu3SbS4 is a promising thermoelectric material because it contains non-toxic, economical, and earth-abundant components. This study refers to the practical synthesis of an array of Cu3Sb1−xPbxS4 (x = 0–0.02) samples through the process of melting response, sulfuration technique, and plasma activated sintering. XRD and SEM analysis show that all the Cu3SbS4-based samples are pure phases. Based on analyses employing density functional theory (DFT), the band gap of Pb-doped Cu3SbS4 increases from 0.57 eV to 0.89 eV, alleviating the bipolar. The thermoelectric performance of Pb doped Cu3SbS4 is improved due to the band convergence and the increase of conductivity. Moreover, the Vicker’s hardness of Pb-doped Cu3SbS4 samples is 2.8 GPa, and the ratio of c/d is 1.6, indicating that the Pb-doped Cu3SbS4 samples exhibit high mechanical properties.