Coordination‐Retarded Crystallization via Amino Acid Amide Hydrochloride for >26% Antisolvent‐Free Perovskite Solar Cells

ABSTRACT The antisolvent‐free spin‐coating of FAPbI 3 films is attractive for the convenient manufacturing of perovskite solar cells (PSCs) and potential for upscaling. However, this process is highly prone to imbalanced crystallization due to the unsatisfied supersaturation rate, resulting in poor crystalline quality and the generation of defects. Herein, we investigate a series of amino acid amide hydrochlorides to systematically regulate the crystallization kinetics of FAPbI 3 in inverted (p‐i‐n) PSCs. Among them, L‐phenylalaninamide hydrochloride (PAH) exhibits exceptional coordination with Pb 2+ , more effectively retarding the crystallization process. By coordinating with Pb 2+ and forming hydrogen bonds with FA + , PAH successfully hinders the binding between the lead‐iodide framework and FA + , transforming the imbalanced, rapid growth into a controlled, slow crystallization process. This promotes the high‐quality crystallization of the films and increases the average grain size to 1.11 ± 0.01 µm. Furthermore, PAH can also play a role in defect passivation, substantially reducing the trap‐state density of the films. As a result, the PAH‐added PSCs achieve an outstanding power conversion efficiency (PCE) of 26.15% and 20.22% for mini‐modules (93.1 cm 2 ). Moreover, the encapsulated devices demonstrate excellent long‐term operational stability, retaining 82.44% of their initial efficiency after 1000 h of continuous maximum power point tracking (MPPT) under 1‐sun illumination.