5-Acetylsalicylamide for defect passivation & crystallization regulation in inverted perovskite solar cells.

We introduce 5-acetylsalicylamide (5-ASA), a pharmaceutical intermediate, as an additive in FA0.95Cs0.05PbI3 perovskite ink. Machine learning (ML) screening and density functional theory (DFT) calculations reveal it simultaneously passivates undercoordinated Pb2+ and iodide vacancies defects, while modulating crystallization. The resulting films exhibit large grains, higher crystallinity, and lower defect density, leading to an enhanced power conversion efficiency (PCE) of 22.12% in inverted devices.