Top‐Interface Passivation With Morpholine‐4‐Carboximidamide Hydrochloride Enables 25.79% Efficiency and Highly Stable Air‐Processed n‐i‐p Perovskite Solar Cells

Organic‐inorganic hybrid perovskite solar cells have achieved remarkable progress, with certified efficiencies exceeding 27%. However, their susceptibility to moisture and oxygen‐induced degradation necessitates fabrication in inert atmospheres, hindering scalable production. Ambient‐air processing, critical for commercialization, remains challenging due to instability at the perovskite/hole‐transport layer interface. This study introduces morpholine‐4‐carboximidamide hydrochloride as an interfacial modifier. The amidine group effectively passivates the [PbI 6 ] 4− lattice via Pb 2+ coordination and I − hydrogen bonding. The COC moiety further coordinates Pb 2 + , forming a protective layer that suppresses defect formation and blocks environmental ingress. The modified devices, fabricated in air, achieve a champion efficiency of 25.79%. Unencapsulated devices retain 95.22% of their initial performance after 2400 h in 15%–25% relative humidity. This work provides a practical strategy for air‐processed, high‐performance perovskite photovoltaics with enhanced stability.