Enhancement of thermoelectric performance by Ag/Bi/Fe co-doping into Cu3SbSe4 ceramics for green thermoelectric applications

Cu3SbSe4 is recognized for its abundant elemental availability, cost-effectiveness, and non-toxic properties, making it a promising candidate for thermoelectric applications at medium temperatures. This study explored the preparation of Bi/Fe, Ag/Fe, and Ag/Bi double-doped Cu3SbSe4 ceramics using vacuum melting and cold isostatic pressing techniques. The focus was on examining the influence of these dopants on the microstructural and thermoelectric performances of Cu3SbSe4. The analysis revealed the presence of Cu3SbSe4 and Cu2_xSe phases in the doped samples. Double doping optimized the carrier concentration, increased the effective mass, and significantly enhanced the electrical conductivity from 12.45 to 64.01 S cm_ 1. Notably, the power factor of the Cu2.85Ag0.15Sb0.985Bi0.015Se4 sample reached 649.1 mu Wm_ 1K_ 2 at 573 K. Furthermore, the thermal conductivity was significantly reduced to 0.73 W/mK. The maximum ZT value of the Cu2.85Ag0.15Sb0.985Bi0.015Se4 sample was 0.47 at 573 K. These breakthrough results demonstrate that dual doping markedly enhances the thermoelectric properties of the Cu3SbSe4 system.