Analytical modeling and numerical investigation of grain size effects on polycrystalline perovskite based Thin-Film solar Cells: Performance insights and implications

Abstract

The potential of polycrystalline perovskite solar cells (PSCs) for high efficiency at low production costs has attracted significant interest. However, grain boundaries (GBs) introduce complexities in the polycrystalline structure that can either enhance or diminish device performance. This study examines the effect of grain size on PSC efficiency through analytical modeling and SCAPS-1D simulations. Our findings highlight the critical role of GBs, showing that larger grain sizes generally improve efficiency by extending charge carrier lifetimes and reducing recombination rates. However, there is a saturation point beyond which further increases in grain size yield diminishing returns, affecting key photovoltaic metrics, such as power conversion efficiency (PCE), open-circuit voltage (Voc), short-circuit current density (Jsc), and fill factor (FF). We also investigated the impact of GB defect density on PSC performance, finding that higher defect densities significantly increase recombination rates, thereby reducing overall PCE. These insights emphasize the importance of optimizing grain size and controlling defect densities to enhance the stability and performance of PSCs. Our research provides valuable guidance for improving perovskite-based solar technologies.