Three-Dimensional to Layered Halide Perovskites: A Parameter-Free Hybrid Functional Method for Predicting Electronic Band Gaps

Accurate prediction of electronic band gaps in halide perovskites is crucial for optoelectronic applications. Standard hybrid functionals like HSE and PBE0 often fail to predict band gaps for 3D and layered perovskites. This study evaluates the doubly screened dielectric-dependent hybrid (DSH) functional for Pb- and Sn-based 3D and layered perovskites. The DSH functional, with material-dependent screening parameters derived from the dielectric constant, accurately predicts band gaps for 3D perovskites when considering local disorder. For layered perovskites, using average dielectric constants tends to overestimate band gaps. We propose using the dielectric constant of respective 3D perovskites for DSH screening, improving predictions for layered structures of various organic spacers. PBE0 band gaps closely match DSH values, especially for iodides, while the HSE functional underestimates band gaps due to missing long-range dielectric screening. This efficient ab initio framework can facilitate the design of advanced optoelectronic devices based on 3D and layered perovskites and their heterostructures.