Nature Communications, Published online: 14 July 2026; doi:10.1038/s41467-026-75053-1 Moisture and oxygen sensitivity during blade coating hinders scalable perovskite solar cells. Duan et al. add dipropylammonium trifluoroacetate to form a self-assembled protective surface layer that stabilizes intermediates, reduces defects, and enables high efficiency, air-processed devices.