Mechanical stability and optoelectronic potential of halide perovskites AXCl3 (A = Ca, Sr; X = K, Rb): A DFT study

The current work was perform by first-principles calculations of the structural stability, electronic band structure and density of states, and optical responses, of Halide Cubic perovskite AXCl₃ (A = Ca, Sr; X = K, Rb) compounds using density functional theory (DFT) within the generalized gradient approximation (GGA). The optimized lattice parameters and ground-state energy calculations confirmed the structural stabilities of these compounds.

The electronic structure calculations show that all compounds are indirect band semiconductors, which are excellent candidates for optoelectronic applications. Furthermore, optical responses were investigated, including the conductivity, optical dielectric function, refractive index, reflectivity, and absorption coefficient. The optical dielectric function and refractive index of both materials CaRbCl₃ (2.89) and CaKCl₃ (2.70) indicate a strong optical response in the visible and ultraviolet regions. In optical reflectivity CaKCl₃ and CaRbCl₃ exhibit strong reflectance in the UV region with maximum values of 0.80 at 13.29 eV and 0.79 at 13.04 eV, respectively, which are indicated for UV-reflective coatings. Optical Absorption coefficient analysis suggests strong photon absorption in the UV and visible ranges, indicating the potential of these compounds for use in photovoltaic and UV photodetector applications. All elastic responses indicate mechanical stability. These results provide valuable insights into the potential use of AXCl₂ compounds in optoelectronic and energy-related applications.