Effective Defect Passivation via Molecular Interactions Based on Amine-Functionalized Ionic Liquid for Perovskite Solar Cells

Defectpassivation containing ionic liquids (ILs) on perovskitefilms has been proven to be an extremely effective strategy for highlyefficient perovskite solar cells (PSCs). However, the exact interactionmode between the ILs and perovskite crystals and the microcosmic mechanismof the structures of ILs on the devices are not clear. Here, we incorporatedan amine-functionalized IL for effective defect passivation on theperovskite films. The amine-functionalized IL interacts with Pb2+ and X (-) in perovskite crystals, whichcan effectively passivate defects and regulate the perovskite crystalgrowth, forming high-quality perovskite films. The microcosmic mechanisminvestigation reveals that the effective defect passivation and defectmigration suppression due to the amine-functionalized IL facilitate the improvement of the photovoltaic performance of the PSC devices.