Ambient‐Air Fabrication of Efficient and Stable Perovskite Solar Cells via Ionic Liquid–Assisted Laser Shock Annealing

The commercialization of formamidinium‐based perovskite solar cells (PSCs), despite their certified power conversion efficiencies exceeding 27%, is significantly hindered by their intrinsic phase instability under ambient conditions, particularly in high humidity. Developing fabrication protocols that can directly produce high‐performance devices in air is therefore a critical research objective. Current strategies often struggle to simultaneously control crystallization kinetics and prevent environmental degradation during processing. In this work, we address this challenge through a synergistic materials and processing approach. We incorporate the hydrophobic ionic liquid BMIMPF 6 into the perovskite precursor and employ laser shock annealing to enable fabrication in high‐humidity air (~70% RH). The BMIMPF 6 additive functions by modifying crystallization kinetics and passivating defects during the film formation. The subsequent laser shock annealing induces rapid microstructural densification. This combined processing results in a pinhole‐free morphology with improved crystalline order and embedded ionic liquid molecules within the lattice. As a result, the champion devices (with PEAI) fabricated entirely in ambient air achieved a power conversion efficiency of 23.50% with negligible hysteresis and exhibited exceptional stability, maintaining 100% of their initial efficiency throughout 700 h of continuous operation, thereby validating the robustness of this approach for ambient‐air production of high‐performance PSCs.