High-efficiency and stable perovskite solar cells <i>via</i><scp>dl</scp>-methionine-enhanced crystallization and defect passivation

As an emerging photovoltaic technology, perovskite solar cells (PSCs) have become a research hotspot due to their excellent photoelectric conversion efficiency (PCE) and low-cost manufacturing process. Enhancing the crystallization quality of perovskite films and mitigating defects through material engineering are crucial for improving the performance of PSCs. In this study, a naturally occurring amino acid, DL-methionine, is incorporated as an additive to enhance the crystallization quality and passivate defects in perovskite films. The results show that the appropriate concentration of the DL-methionine additive can not only improve the crystallization kinetics of perovskite films but also reduce the defects of perovskite films through its coordination with perovskite ions, thereby reducing defect-assisted recombination. Finally, the optimized PSCs based on the DL-methionine additive obtained the highest power conversion efficiency of 24.72%, significantly higher than those without the DL-methionine additive (21.83%). Moreover, the stability of PSCs is significantly improved with the DL-methionine additive. This work demonstrates the potential of DL-methionine as an effective passivation agent for high-efficiency and stable PSCs.