Investigation of Epitaxial Misfit Strain Influence at the CsSn(I1-xBrx)3/SnO2 Interface on Photovoltaic Parameters in Cu2O/CsSn(I1-xBrx)3/SnO2 Perovskite Solar Cells

This work involves the numerical simulation of the photovoltaic performance of a single perovskite solar cell based on the Cu2O/CsSn(I1-xBrx)3/SnO2 structure, utilizing a lead-free inorganic perovskite absorber layer CsSn(I1-xBrx)3 with variable bromine content represented by the ratio x. The study aims to evaluate performance fluctuations due to misfit deformation effects at the interface between the SnO2 electron transport layer (ETL) and the absorber on photovoltaic parameters. The simulation model incorporates variations in the physical parameters of the device layers dependent on the ratio x. This enables the calculation of bandgap energy fluctuations according to strain theory and assesses the resultant impact on photovoltaic parameters due to strain at the SnO2/CsSn(I1-xBrx)3 interface. Performance results are presented as a function of bromine composition x, considering both the presence and absence of deformation effects. The study clearly demonstrates the significant impact of misfit deformation on bandgap energy fluctuation, emphasizing the need to optimize bromine content to balance deformation effects and achieve optimal performance. Specifically, the results show a maximum efficiency of 19.72% at x=0.56 for the undeformed structure, and 19.30% at x=0.50 for the deformed structure. This study refines simulation results and underscores the critical role of deformation engineering in modulating energy gaps.