Improving the performance of FAPbI₃ perovskite solar cells using a self-assembled monolayer

In halide perovskite solar cells, the interfaces between the charge-transporting materials and perovskite significantly control the photovoltaic performance of the devices. In this simulation-based work, we introduce fullerene molecules as an interlayer between the front electrode and the perovskite layer to passivate surface defects and mitigate degradation arising from the direct contact between the electrode and the perovskite. Through SCAPS-1D simulation, we suggest that introducing a self-assembled monolayer reduces recombination losses, facilitates charge-carrier extraction, and improves band alignment in perovskite solar cells. We also evaluate the solar cell performance by tuning the perovskite layer thickness, trap-state density, shallow-acceptor density, parasitic resistances, and operating temperature to optimize the photovoltaic designs. The incorporation of this molecular modifier enables the simulation of conventional FAPbI₃-based perovskite solar cells with an efficiency of 24.07% under typical illumination conditions. Moreover, the optimized devices show high thermal stability, retaining 77% of their initial performance at 450 K.