Influence of the Dimensionality and Organic Cation on Crystal and Electronic Structure of Organometallic Halide Perovskites

Layered
perovskites open a plethora of possibilities for tuning organometallic
halide perovskite (OMHP) properties via the incorporation of larger
organic cations. Promising applications of this increased structural
freedom include enhanced chemical stability and tunable exciton binding.
Owing to the larger cation, crystal and electronic structures vary
with layer stacking, having layered bulk and a monolayer as limiting
cases. Using ab initio calculations, here we study
the atomic and electronic structures of such a layered material, (C6H5C2H4NH3)2PbI4, which has recently attracted attention as
a promising solar cell material. The reduction of layer thickness
between the bulk and a monolayer is investigated and compared to that
of the benchmark OMHP, (CH3NH3)­PbI3, showing that the bulkier C6H5C2H4NH3 cations largely preserve the two-dimensional
nature of the electronic structure in the layered bulk OMHP.