Stabilizing perovskite fabrication in ambient air

• Introducing n-butylammonium thiocyanate (nBASCN) as a wet-film additive stabilizes perovskite crystallization under ambient air conditions. • The additive prevents premature nucleation and promotes uniform film growth, mitigating moisture-induced degradation. • This approach enables scalable manufacturing of high-performance perovskite solar cells without requiring tightly controlled environments. • The strategy addresses a critical gap in existing methods for ambient-air fabrication, offering a pathway to commercial viability.