Comprehensive device modeling and performance analysis of (Cs, FA)Pb(I, Br)3 based perovskite–silicon tandem solar cells

The utilization of perovskite films as the top subcell to form a perovskite–silicon tandem solar cell has emerged as an attractive approach to achieve higher power conversion efficiency (PCE) that could surpass the Shockley–Queisser limit for single silicon junction. Despite these efforts, precisely understanding and predicting the underlying mechanism necessary for obtaining higher PCE remains a challenging task. In particular, the absorption due to back electrode reflection during calculations has often been neglected, resulting in an underestimation when comparing theoretical calculations to experimental conditions. In this study, we conduct a comprehensive investigation of perovskite–silicon tandem solar cells with considering the back electrode reflection to study the detailed influence on film quality of perovskite films, where a detailed analysis of multiple factors such as bulk and interface defects, doping levels, and carrier mobility from (Cs, FA)Pb(I, Br)3 has been conducted to unveil their effects on device performance. Our results revealed that lower bulk/interface defect concentrations and higher carrier mobility are critical factors contributing to the best device performance, where the highest PCE would reach up to 37.40%. Further comparison with experimental results also confirms the importance of employing effective methods to reduce surface/interface trap densities in order to enhance overall performance. These findings offer valuable theoretical insights for the guidance of experimental designs of perovskite–silicon tandem solar cells.