DFT study of structural, optoelectronic and thermoelectric properties of Cs2/Rb2InAgBr6 compounds for energy harvesting applications

Cs2/Rb2InAgBr6 double perovskites are investigated by employing density functional theory (DFT). We utilized PBE-GGA and mBJ potential approximation for the calculation of the structural and optical characteristics, and the BoltzTrap code is used for the thermoelectric characteristics. The mechanical tolerance factor and elastic constant are used to examine the stability of the material, while Pugh's and Poisson's rations are used to verify the ductile nature. Due to the direct band gaps of Cs2/Rb2InAgBr6 with values 1.45/1.48 eV, these compounds can favorably be used in solar cell devices. Further, we calculated electron density, thermal conductivity, Hall coefficient, Seebeck coefficient, susceptibility, specific heat capacity, and susceptibility (chi) for these materials. The Seebeck coefficient and power factor value indicate that these materials are potential candidates for thermoelectric purposes. These results of optical characteristics show their enormous potential for use in fabricating high-performance photovoltaic devices.