High-speed and sensitivity near-infrared organic photodetector achieved by halogen substitution strategy for optical wireless communication

High-speed and sensitivity solution-processed organic photodetectors (OPDs) have drawn great attention for their promising applications in next-generation optoelectronics, including optical communication, imaging, autonomous driving, and military security. However, current OPDs commonly suffer from slow response speed due to low charge mobility, significantly hindering their applications in optical wireless communication. Herein, a pair of nonfullerene acceptors (NFAs), featuring a prominent π extension in the central units with respect to Y6, are synthesized with the same backbone but different halogenations in end cap groups, namely, CH-4Cl and CH-4F. The OPD based on CH-4Cl exhibits a remarkably short response time of 270 ns (λ = 850 nm) and detectivity of >1013 Jones in a self-powered mode, improving 34% and 500% compared to the values of OPD with CH-4F NFA, respectively, which ranks the highest speed among self-powered solution-processed binary OPD-based on NFAs. This outstanding performance is attributed to the low trap states and energetic disorders of OPDs with CH-4Cl. Furthermore, the high-speed OPD demonstrates a promising application in high-speed optical wireless communication.