Electronic Structure of (Organic‐)Inorganic Metal Halide Perovskites: The Dilemma of Choosing the Right Functional

Organic–inorganic metal halide perovskites (HaPs) are intensively studied for their light-harvesting properties. Owing to the interplay between strong electron–electron interaction and spin-orbit coupling (SOC), quantitative theoretical description is still a challenge as evidenced by wide variety of results available in literature. Here, various methodologies computing electronic structure evaluated, also accounting SOC. More specific, G W $GW$ approach well variants hybrid functionals PBE0 HSE at center investigations. For both functionals, methods determine mixing parameter α explored, HSE, impact screening-parameter ω investigated. An extensive investigation PbI2, precursor many HaPs, leads conclusion that with tuned density-based method most suitable obtaining band gaps comparable 0 $G_0W_0$ results. Moreover, this methodology transferable CsPbI3, same behavior expected entire family lead–iodine perovskites.