Improvement in Efficiency and Reproducibility for FAPbI3 Solar Cells with Rapid Crystallization

Clarifying the crystallization process of the perov-skite FAPbI3 film is quite an important pathway for improving the performance of perovskite solar cells, and the annealing time is a key factor to control the nucleation and crystal growth. However, the existing electrodeposition method lacks systematic studies on the growth of the perovskite FAPbI3 film. Herein, we manipulate the annealing time precisely for growing a pure alpha-FAPbI3 perovskite film in the electrodeposition-assisted method. The perovskite pure alpha-FAPbI3 film can be synthesized by fast annealing in only 1 min, and the as-prepared perovskite film shows high solar light absorption capacity and large grains. Thus, the corresponding solar cells based on alpha-FAPbI3 show the best power conversion efficiency (PCE) of 13.33%, which is 32% higher than that of FAPbI3 solar cells annealed for a long time (20 min). More importantly, all of these PCE variances do not exceed 1% under different annealing times, indicating the high reproducibility of the perovskite solar cells based on this rapid crystallization method. With a phenethylammonium iodide passivation layer, the PCE can even be improved to 14.02%.