Thermoelectric properties of Cd doped tetrahedrite: Cu12−xCdxSb4S13

The effect of Cd doping on the thermoelectric properties of synthetic tetrahedrites Cu12−xCdxSb4S13 (x = 0, 0.25, 0.5, 0.75, 1, 1.25 and 1.5) was studied. Powder X-Ray Diffraction and electron probe micro analysis confirm the presence of tetrahedrite as main phase with a trace of impurity phases. The influence of Cd substitution on Cu was confirmed by a systematic increase of electrical resistivity and Seebeck coefficient with doping content. Power factor decreased with doping content mainly affected by the significant increase in electrical resistivity. The total thermal conductivity was found to be reduced from 1.32 W/m-K for the sample with x = 0 to 0.71 W/m-K for the sample x = 0.75 at 623 K but showed an abrupt increment for x = 1 and decreased for the subsequent samples with x = 1.25 and x = 1.5. A combined result of power factor and thermal conductivity leads to thermoelectric figure of merit, zT = 0.9 at 623 K for Cu11.25Cd0.75Sb4S13.