Simultaneous optimization of the overall thermoelectric properties of Cu3SbSe4 by band engineering and phonon blocking

Abstract It is a challenge to optimize the coupled electrical and thermal transport properties of a thermoelectric material simultaneously. Here, the enhancement of overall thermoelectric properties in Cu 3 SbSe 4 has been demonstrated through Te substitution. The results display that the simultaneous optimization of the Seebeck coefficient, electrical conductivity and thermal conductivity is realized after Te-doping and thus yielding considerable enhancements in ZT values in the whole temperature range as comparison to that of pristine Cu 3 SbSe 4 . In Te-doped Cu 3 SbSe 4 system, the reduction of electrical resistivity is due to the narrowed bandgap; the enhanced Seebeck coefficient stems from the increased density of states near the Fermi level; and the suppressed thermal conductivity is related to the introduced phonon blocking from point defect scattering or softening of chemical bond interaction. This work can also offer a referential route to boost the overall thermoelectric properties by isovalent doping with heavy element for other thermoelectric materials.