Robust, flexible and broadband photodetectors based on van der Waals graphene/C60 heterostructures

Low-dimensional carbon materials, such as conducting graphene, semiconducting C60 and their hybrids, have recently received a great deal of attention for the potential applications in low-cost flexible and wearable nanoelectronics, due to their remarkable mechanical, electrical and optoelectronic properties. While graphene exhibits intrinsically weak absorption and C60 is typically associated with low carrier mobility and short exciton diffusion length, the marriage of two materials is a synergetic route to overcome these technical short-comings. Here, we fabricate a van der Waals bonded graphene/C60 hybrid on a plastic substrate to demonstrate a highly sensitive flexible photodetector. Intimate electronic coupling across the all-carbon interface allows highly efficient interfacial charge transfer, which effectively dissociates the electron-hole pairs and leads to significant photoresponse across ultraviolet to near-infrared (∼104 A/W @ 405 nm). Thanks to remarkable absorption of C60, it enables the detection of weak signals including those from a lighter and fluorescent lighting. Simultaneously, the photodetector exhibits extraordinary mechanical flexibility, allowing excellent electric conductivity and stable light detection under quite large tensile strain. Furthermore, the flexible devices still exhibit a satisfactory photoresponse after 6 months, indicating the excellent environmental robustness. This scalable all-caron hybrids may provide a viable route to produce the high-performance flexible optoelectronic devices.