MACl-Induced Controlled Crystallization in Sequentially Deposited Perovskites for High-Efficiency and Stable Perovskite Solar Cells

Perovskite solar cells are attracting more and more attention due to their higher absorption and low cost. However, fabricating the perovskite film with high crystallinity and ideal morphology, which presents large-size and uniform particles with fewer grain boundaries, still needs further improvement. Herein, we introduce MAPbCl3 crystals into the PbI2 film in the sequential deposition process, which obtained the controlled crystallization in perovskite films. The perovskite films induced by MAPbCl3 have stronger crystallinity, fewer defect states, and larger grain size, reducing carrier recombination and improving carrier transfer. The optimized perovskite solar cell (PSC) has achieved a power conversion efficiency of 20.97%. Furthermore, the stability of PSCs has also been enhanced due to the reduced grain boundaries impeding moisture diffusion. This strategy can be applied in other solution-based fabrication processes to improve the photovoltaic performance of PSCs.