Exploring optoelectronic, thermodynamic and thermoelectric characteristics of ternary halide perovskites CaRbX3 (X = Cl or I) for photovoltaic and thermoelectric applications: a DFT insight

In this study, we systematically examined the physical properties of CaRbX3 (X = Cl or I) perovskites by employing the (FP-LAPW) method within the (GGA) and GGA + mBJ approximations. The optimized structural parameters of both studied compounds are in good agreement with previous theoretical results. The electronic characteristics reveal that the CaRbX3 compounds are direct band gap (Gamma-Gamma) semiconductors with band gap values slightly larger than the previous theoretical results. The optical properties are investigated for the first time indicating the possibility of using these materials in solar cells and photovoltaic technologies. Additionally, the thermodynamic and thermoelectric properties reveal that the studied halogen perovskites are possible candidates for the application in thermoelectric technology through their favorable factor of merit under room temperature.