Optical Properties of Chiral Perovskites: The Role of Electrostatic Embedding in Correcting the Accuracy of Exchange-Correlation Functionals

The accurate modeling of the excited state landscapes in chiral materials requires an optimal balance between the description of their electronic structure and the influence of environmental effects. In this work, using a prototypical lead halide chiral perovskite, we show that embedding a chromophore in point charges has a beneficial effect in correcting the spurious representation of charge-transfer states arising from hybrid or semilocal approximations within density functional theory (DFT). Notably, the effect of the embedding also outperforms the benefits induced by the range-separated functionals. While the nature of the state remains similar, we demonstrate that the addition of point charges significantly decreases the electron-hole distance. The combination of hybrid functionals with embedding provides the best description of the experimental absorption spectrum, with the only exception being excitonic states that cannot be reproduced when considering a model constituted by a single cell.