Effect of Spin-orbit Coupling Consideration in DFT Calculations on Calculated Optical Properties of Mixed Chloride-Bromide Perovskites

Mixed Halide Perovskites have become a key focus in the optoelectronic field due to their compositionally tunable band gaps and outstanding performance in photovoltaics applications. In this study, the effects of incorporating spin-orbit coupling (SOC) in Density Functional Theory (DFT) based calculations of optical properties for MAPb(Cl<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</inf>Br<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1-x</inf>)<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> were investigated. Incorporating SOC reduces the DFT based band gap overestimation by 42% in Mixed Chloride-Bromide Perovskites. However, the band gap variation pattern with Chloride and Bromide composition remains identical, making Non-consideration of SOC adequate for identifying band gap variation patterns.