A Flexible 2D Covalent Organic Framework Film for Near‐Infrared Visual Adaptation

Abstract 2D covalent organic frameworks (2D‐COFs) have the potential to be employed as photoelectric active layers due to high crystallinity, structural tunability, and their graphene‐like 2D layered features. However, photosensors based on 2D‐COFs with near‐infrared (NIR) visual adaptation and flexibility remain challenges in this field. In this study, a donor–acceptor 2D‐COF film is synthesized via a liquid‐liquid interfacial polymerization reaction, exhibiting flexibility and broad‐spectrum light absorption properties even spanning NIR. Moreover, the as‐prepared visual bionic devices demonstrate photonic adaptive behavior with excellent light intensity and voltage dependences, which can be successfully applied in wireless optical communications. This TpDPP‐Py (TpDPP: 5,5′‐(2,5‐bis(2‐ethylhexyl)‐3,6‐dioxo‐2,3,5,6‐tetrahydropyrrolo [3,4‐c]pyrrole‐1,4‐diyl)bis(thiophene‐2‐carbaldehyde), Py: 1,3,6,8‐tetrakis(4‐aminophenyl)pyrene) COF film will largely promote the development of NIR neuromorphic optoelectronics, thus expanding applications in sustainable and portable devices based on flexible COF film.