The effective mass, fitness function and enhanced thermoelectric properties in CuSbS2 for p-type thermoelectric material applications: Density functional theory approach

Abstract The thermoelectric properties, electronic fitness function (EFF) and transport inverse effective mass (m*) of CuSbS2 were predicted using Density Functional Theory along with Boltzmann transport theory. The Generalised Gradient Approximation as embedded in projector – augmented wave was used in this work. From our results, CuSbS2 exhibits an indirect narrow bandgap of 0.78 eV. The Power factor (PF) as well as the Seebeck coefficient (S) increase with temperature at every hole carrier concentration, and while PF is temperature dependent, S is almost independent of temperature for electron carrier concentrations making the electron minority carrier in the material. It was also revealed that this material has light m* and high EFF at 300, 500, 700 and 800 K. The obtained EFF implies that the thermoelectric performance of this material increases with temperature and can also be enhanced via doping. We obtained an electronic Figure of merit of 0.2 at room temperature which increase to 0.49 at 800 K. These results revealed that CuSbS2 is a promising P-type thermoelectric material.