Role of heterostacking of 2D lead chloride perovskites on photoluminescence

Two-dimensional organic-inorganic hybrid lead halide perovskites are of interest for photovoltaic and light-emitting devices due to their favorable properties that can be tuned. Here, we use density functional theory to model two-dimensional lead halide perovskites of different thicknesses and combined into vertical heterostructures. Excited-state dynamics treated by reduced density matrix method is used to examine the excited-state optoelectronic properties of the perovskite models. Nonadiabatic couplings were computed based on the on-the-fly approach along a molecular dynamics trajectory at ambient temperatures. The dynamics of electronic degrees of freedom were calculated using density matrix-based equation of motion for electronic degrees of freedom. We observe that the vertical stacking of two-dimensional perovskites into heterostructures shows an increase in photoluminescence intensity by two orders of magnitude when compared to the individual two-dimensional perovskites.