Enhanced Interlayer Interactions in Tin Halide Perovskite Solar Cells with a Fluorinated Fullerene Derivative

Lead-free tin halide perovskite solar cells (TPSCs) have recently made significant progress in power conversion efficiency (PCE). However, the presence of mismatched energy levels and weak interlayer interactions between the electron transport materials (ETMs) and tin perovskites has limited the achievable PCE. Here, a new fluorinated fullerene derivative, C60-FTPA (F12), was designed and synthesized to construct a binary ETM with C60-ETPA (F6) reported in our group, resulting in a reduction in defects and improved molecular structure ordering. Furthermore, the binary ETM exhibited a stronger interaction with the tin perovskite and delivered a PCE up to 11.93%.