Maximizing efficiency: Numerical modeling and optimization of 2-terminal perovskite/silicon tandem devices with different bottom cell structures

Two-terminal perovskite/silicon (Si) tandem solar cells have made significant progress in terms of efficiency and are considered suitable candidates for the next generation of photovoltaic devices. However, research on Si bottom cell optimization is limited, with optimization being conducted only within a specific structure reported as high efficiency. To present more general and higher efficiency possibilities, optimization is necessary not only for the perovskite and interlayer but also for each bottom Si solar cell structure. In this study, we proposed a numerical modeling approach for analyzing and optimizing the effects of optical and electrical properties in 2-terminal tandem structures. First, the properties for each layer were discussed to minimize optical loss using optical simulations, considering the recently reported high-efficiency 2-terminal perovskite/Si tandem system. After fixing the top perovskite and recombination layer using these properties, each bottom Si structure, which is divided into homojunction (PERC and TOPCon structure) and heterojunction (HIT structure), was electrically simulated. The characteristics of Si bottom cells were identified based on bulk properties (bulk lifetime and resistivity). Consequently, we proposed an improvement method and structure capable of achieving maximum possible efficiency of more than 30 % as a tandem device for each bottom cell structure.