Self-Powered Organic Phototransistors with Asymmetrical van der Waals Stacking for Flexible Image Sensors
Jing Zhao, Qianqian Du, Xialian Zheng, Yunlong Liu, Shuhong Li, Wenjun Wang, Fengqiu Wang, Shuchao Qin
Abstract
Organic materials have drawn significant interest for next-generation advanced optoelectronic devices or systems owing to their extraordinary light absorption, intrinsic flexibility, and low-temperature, large-scale processability. While for high-performance organic photodetectors, their restricted carrier mobility, limited diffusion length, and high binding energy of Frenkel excitons have long been regarded as the major challenges. In this paper, we report a sensitive organic rubrene crystal/graphene heterostructure photodetector. Especially, using an asymmetrical van der Waals stacking configuration, we realized self-powered photon detection in such a graphene-based organic heterostructure device. Long-range exciton diffusion of the rubrene single crystal, the efficient exciton dissociation, and the ultrafast charge transfer near the heterointerface enabled several commendable performances, including the great responsivity of 8 × 10 5 A/W, specific detectivity of >10 12 Jones, and a fast response speed (ca. 20/70 μs). Encouragingly, the device exhibits excellent mechanical flexibility, remaining good conductivity, and stable light detection, even under harsh strain and after hundreds of cycles. Utilizing their outstanding photoresponse, we demonstrate fast-speed imaging applications on rigid and flexible substrates. Our work offers a practical strategy for developing high-performance, self-powered organic photodetectors for future wireless photon detection and high-speed imaging applications.