In situ coating strategy for flexible all‐perovskite tandem modules: A new path toward high‐efficiency flexible photovoltaics

Abstract Flexible perovskite solar cells hold great potential for lightweight and conformal photovoltaics but their power conversion efficiency (PCE) still lags behind rigid counterparts, particularly in large‐area modules, due to challenges in forming high‐quality films on flexible substrates. To address this challenge, Tan et al. present a scalable gas‐quenching‐assisted in situ additive coating strategy that enables dynamic control of crystallization and synergistic optimization of bulk and interfacial properties (Nat. Photon. 2025, 19, 1255–1263). This approach yields wide‐bandgap perovskite films up to 30 × 40 cm2 on polyethylene terephthalate (PET) under ambient conditions, featuring high crystallinity, low defect density, and pinhole‐free interfaces. Using this method, they achieve a 27.5% PCE in flexible all‐perovskite tandem cells (active area of 0.049 cm2) and a certified 23.0% efficiency in large‐area modules (aperture area of 20.26 cm2). Slot‐die‐coated wide‐bandgap modules (aperture area of 804 cm2) exhibit excellent flexibility, retaining 97.2% efficiency after 10,000 bending cycles and outstanding thermal and operational stability. This work narrows the performance gap between flexible and rigid tandems, advancing scalable, high‐efficiency flexible photovoltaics.