Scaling of the free and the relaxed exciton in perovskites (RNH3)2(CH3NH3)p−1PbpI3p+1 large sized monolayers

Abstract

The investigation of the fluctuations and their influence on the exciton in the perovskite structure is topical. These fluctuations can be due to the prolongation of the annealing or the increasing of the temperature in the perovskite monolayers. This fact generates structural imperfections, which may arise from vacancies and lattice structural defects. In this work, we propose a theoretical approach in order to study the optical properties characterized by excitons in (RNH3)2(CH3NH3)p−1PbpI3p+1 perovskite structures. For high quality samples, we investigate the free exciton taking into account the quantum and the dielectric confinements. For low quality samples, we model the surface disorder of perovskite monolayers through a randomized potential in the layer plane. Finally, we investigate the dependence of the perovskite layer thickness (p-value) on the shift between the relaxed exciton compared to the free exciton, and we show that our model allows us to simulate the experimental spectra of the exciton states.