Abstract
Halide perovskites are an intriguing renewable energy materials that may assist in addressing the world's energy scarcity. The Goldsmith tolerance factor (0.99 and 1.00) and negative formation energy guarantee the examined materials' structural and thermodynamic stabilities. The Poisson's and Pugh's ratio proves the reviewed materials' ductile nature. K/RbOsCl(3) has electronic band gaps of 1.37 eV/1.39 eV and the highest light absorption in the ultraviolet and visible areas, enhancing its efficacy for solar cells and other optoelectronics technologies. The highest Seebeck coefficient and electrical conductivity render these materials feasible for thermoelectric properties. KOsCl(3) and RbOsCl(3) exemplify figures of merit of 0.89 and 0.88, respectively, at the ambient temperature. Additionally, the Debye model was implemented to figure out thermodynamic parameters such as heat capacity, thermal expansion, Debye temperature, and Grüneisen parameter.