Advancing self-assembled molecules toward interface-optimized p–i–n-type perovskite photodetectors

Perovskite photodetectors have garnered considerable attention owing to their exceptional optoelectronic properties and their promising potential for flexible, high-performance device applications. However, their practical implementation remains limited by poor interfacial quality, high defect densities, and suboptimal carrier dynamics. Here, a self-assembled monolayer of [2-(9H-carbazol-9-yl)ethyl]phosphonic acid was employed to modify an indium tin oxide substrate, aiming to simultaneously enhance perovskite crystallization and charge transport in p–i–n-type perovskite photodetectors. With this surface modification, the optimized device exhibits a significantly enhanced performance, including 15 718%, 2624%, and 27.5% improvements in detectivity, photocurrent density, and response time, respectively. This work offers valuable insights and guidance for improving the performance of perovskite photodetectors through interface engineering.