Band gap engineering of vacancy-ordered halide perovskite Cs2SnCl6 from substitutional doping of Pt (Cs2Sn(1-x)PtxCl6 where x = 0, 0.25, 0.50, 0.75 and 1.00) and its effects on thermoelectric properties using the first-principles approach

Abstract

Researchers have shown substantial interest in vacancy-ordered halide perovskites for non-traditional energy harvesting applications including solar cells and thermoelectric generators. In this study we performed band gap engineering of vacancy-ordered halide perovskite Cs2SnCl6 from substitutional doping of Pt (Cs2Sn(1-x)PtxCl6 where x = 0, 0.25, 0.50, 0.75 and 1.00) and studied its effects on thermoelectric properties using first-principles approach. Thermodynamic stability has been proven by computing the formation energies and the tolerance factors. The band gaps were efficiently reduced to 2.50 eV from 3.61 eV by the band gap engineering approach of Pt doping. Consequently, the materials exhibited improved thermoelectric properties, including low thermal conductivities, high Seebeck coefficients, and high values of ZT. The maximum value of ZT = 2.27 was estimated for x = 1.00. The Pt doping technique can be deemed effective based on the enhanced structural and thermoelectric performance parameters.