Density functional theory analysis of structural, electronic, and optical properties of AInX₃ (A = K, Rb, Cs and X = Cl, Br) perovskites

This study investigates the optoelectronic potential of novel lead-free inorganic metal halide cubic perovskites AInX₃ (A = K, Rb, Cs; X = Cl, Br) using ab initio density functional theory calculations. These compounds exhibit semiconducting characteristics with indirect bandgaps, demonstrating tunability through A-site cation and X-site anion substitutions. A comprehensive analysis of structural, electronic, and optical properties reveals remarkable features, including high dielectric constants, elevated absorption coefficients, low reflectivity, and superior optical conductivity compared to their lead-based counterparts. These features make them promising candidates for next-generation photovoltaic and optoelectronic devices, addressing the toxicity and instability of lead-based perovskites and advancing sustainable optoelectronics.