Abstract
Chiral molecules have shown potential in passivating perovskite solar-cell interfaces and boosting charge transport and have drawn significant research interest. However, the specific passivation mechanisms of different chiral structures on perovskite films and their photoelectric effects require further investigation. In this study, chiral R-, S-, and rac-methylbenzylammonium chloride (MBACl) molecules are used to address interface defects. S-MBACl exhibits the strongest chelation and passivation effects. Kelvin probe force microscopy results show that S-MBACl increases the surface potential differences between dark and illuminated states by 227%, from 39.67 to 129.91 mV, and enhances electron-hole separation. Consequently, the power conversion efficiency (PCE) of S-MBACl-modified devices is 24.07%, which is 109% times that of the pure perovskite sample. The PCE of unencapsulated S-MBACl-modified perovskite solar cells remains at 89% of the initial value after aging at 25 °C for 2400 h in the N(2) atmosphere. This study provides valuable insights for future studies on chiral passivation molecules.