DFT prediction of double perovskites A2BʹRhCl6 (A = Cs/Rb; Bʹ = Na/K) for green energy technology

Double halide perovskites A₂BʹRhCl₆ (A = Cs/Rb; Bʹ = Na/K) are emerging as promising contenders in optoelectronic and energy-related applications due to their tunable electronic properties and inherent stability. In this study, the structural, electronic, and optoelectronic properties of A₂BʹRhCl₆ compounds were explored using first-principles density functional theory (DFT) calculations. This study thoroughly investigated the structural stability of these phases. The results indicate that these new materials possess favorable band gaps and, consequently, exhibit high optical response, rendering them potential materials for photovoltaic applications. The computed band gap values were 1.79, 1.82, 1.90, and 1.95 eV for Cs₂NaRhCl₆, Cs₂KRhCl₆, Rb₂NaRhCl₆, and Rb₂KRhCl₆, respectively. The optical properties, including the dielectric function, absorption coefficient, refractive index, energy loss function, photoconductivity, and reflectivity, have also been examined to gain further understanding of their electronic characteristics. Within the visible spectrum for A₂BʹRhCl₆ (A = Cs/Rb; Bʹ = Na/K), the absorption coefficients were measured at 10⁵ cm⁻¹. A comprehensive investigation into the thermo-mechanical characteristics was also conducted to fully assess the potential of the herein selected materials. The findings indicate that these compounds hold promise for applications in solar cells and green energy technology.