Electronic and optical properties of mixed-halide perovskites, CsxFA1−xPb(X, X’)3: insights from density functional theory

This study employs density functional theory (DFT) to explore how halide composition and cesium doping influence the electronic and optical properties of mixed-halide perovskites Cs0.15FA0.85Pb(X, X’)3. The computed band gaps follow the halide electronegativity trend: Cl > Br> I resulting in values 1.637 eV, 1.449 eV, and 0.883 eV respectively. These trends remain reliable despite the well-known band-gap underestimation inherent in semi-local functionals which originates primarily from the self-