ABSTRACT Ambient air fabrication of perovskite solar cells (PSCs) is highly desirable for industrial scalability, yet the realization of high efficiency and long‐term stability still typically relies on nitrogen‐filled gloveboxes, a costly and space‐limited strategy that impedes large‐scale deployment. This study introduces di‐tert‐butyl dicarbonate (BOC) as a multifunctional additive that enables the fabrication of high‐performance n‐i‐p PSCs entirely in ambient air. BOC begins to thermal decomposition at 70°C, releasing gases that induce an open porous PbI 2 structure to enhance FAI infiltration. During subsequent perovskite crystallization, residual BOC slowly decomposes, forming a dynamic gas barrier that aligns with the crystallization window. This mechanism suppresses moisture and oxygen induced Pb 2+ reduction and perovskite decomposition, effectively minimizing harmful Pb 0 and unreacted PbI 2 , thereby resulting in high‐quality films with enhanced crystallinity and reduced defects. The champion device achieves a remarkable power conversion efficiency of 26.02%. Furthermore, these devices demonstrate outstanding stability under both environmental storage and operational conditions. After 1800 h of dark storage, they retain over 97% of their initial PCE, and after 1000 h of continuous illumination, they maintain more than 85% of their initial PCE.
Li et al. (Mon,) studied this question.