Low-dimensional perovskite interlayer for highly efficient lead-free formamidinium tin iodide perovskite solar cells

The low-dimensional perovskite interlayer was introduced close to the p-type interface in the inverted FASnI3 solar cells, leading to reduced trap states and suppressed charge recombination. Consequently, a champion power conversion efficiency of 7.05% was achieved, which was one of the highest reported efficiencies for the lead-free FASnI3 solar cells.192