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

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.