Enhancing the efficiency and stability of carbon‐based perovskite solar cells via 5‐AVAI interface modification

Abstract The non‐radiative recombination loss at the interface is a huge obstacle to improving the photovoltaic performance of perovskite solar cells (PSCs), especially carbon‐based PSCs (C‐PSCs). Here, we propose a strategy for synergistic regulation of interface defects and carrier transport through functional groups of long‐chain ammonium salt molecules to form 2D perovskite passivation layers by surface treatment with 5‐aminovalerate hydroiodide (5‐AVAI). The results indicate that the carboxyl group (–COOH) in 5‐AVAI molecules can form coordination bonds with uncoordinated Pb 2+ ions, thereby anchoring to the surface of the perovskite film. Simultaneously, the electrostatic interaction between the amino group (–NH 3 + ) and I − ions in 5‐AVAI inhibits the formation of iodide vacancies, enhances defect passivation, and improves the transport and transfer efficiency of interfacial carriers. The atmospherically generated 5‐AVAI‐modified C‐PSCs exhibited an efficiency of 16.50% and retained 85% of their initial efficiency for 80 days in atmospheric environment.