In Situ Polymerization‐Assisted Crystallization of Open‐Air Blade‐Coated Perovskite Films for Efficient Solar Cells and Mini‐Modules

Abstract Perovskite solar cells (PSCs) have emerged as a promising photovoltaic technology, yet their commercialization is hindered by challenges related to scalability and potential lead leakage. Here, we successfully developed an in situ polymerization strategy that constructs a functional bottom interface layer and a bulk polymer network, enabling controlled crystallization and defects passivation of air‐blade‐coated perovskite film. Specifically, 2‐aminoethyl methacrylate hydrochloride (2‐Amh) was employed as a monomer and deposited on the substrate, where it polymerized during thermal annealing. Upon blade‐coating the 2‐Amh‐incorporated perovskite precursor, a synergistic interaction between the bottom polymer interfacial layer and the in situ formed polymer network within the bulk during thermal annealing significantly enhanced the film uniformity and crystallinity. Moreover, the embedded polymer network effectively mitigates lead leakage from damaged devices and suppresses the oxidation of the I ‐ to I 2 by Ni 3+ . Consequently, the devices based on air‐blade‐coated perovskite films achieve a steady‐state efficiency of 20.78% for 5 × 5 cm 2 mini‐modules (10.80 cm 2 ). For comparison, spin‐coated devices utilized the same strategy also demonstrated high PCEs, though they were not the focus of this work. These findings offer a promising solution for scalable perovskite photovoltaics, addressing both performance and environmental sustainability.