Quantitative analysis of the transient photoluminescence of CH$_{\text{3}}$NH$_{\text{3}}$PbI$_{\text{3}}$/PC$_{\text{61}}$BM heterojunctions by numerical simulations

Transient photoluminescence measurements of lead-halide perovskite layers with electron or hole transport layers provide insights into the interfacial charge transfer and recombination processes. However, analytically describing these measurements over a wide range of timescales is complicated by the combination of different physical effects such as transport within the perovskite, transfer to the transport layer, accumulation of charges and recombination at the interface. Therefore, numerical drift-diffusion simulations of photoluminescence transients as a function of laser fluence and interface properties are used to obtain a quantitative understanding of experimental results. Comparison between experiment and simulation combined with an analysis of the uniqueness of the result yields an interface-recombination velocity that has to be around ∼200 cm s−1 for the perovskite–PC61BM interface in order to be consistent with data obtained at several laser fluence