Graphene photodetector with polydiacetylenes acting as both transfer-supporting and light-absorbing layers: Flexible, broadband, ultrahigh photoresponsivity and detectivity

Abstract

Polydiacetylene (PDA) films are shown enabling the combination of graphene transfer and photodetector fabrication into one step. Under the assistance of PDA, centimeter pieces of graphene can be acquired with free of broken or fractures. The constructed PDA/graphene hybrid films demonstrate ultrahigh, gate-tunable responsivity (R) and detectivity (D*) from UV to visible wavelengths, for instance, statistical R and D* at 320 nm achieves 556 A W−1 and 6.0*1011 Jones at the irradiance of 0.24 mW cm−2, indicating their superior broadband and sensitive detecting abilities. Kinetic response of our devices is not fast as the cost of high responsivity, which, however, can be efficiently amended by applying potential pulses through back gate electrodes. If supported PDA/graphene films on polymer substrate, the devices can still work reliably after being bended 25,000 cycles, and even can respond to light stimulus evidently at a heavily-stretched state created by a completely-folded human finger, revealing their remarkable flexibilities. The developed strategy of killing two birds (graphene transfer and functionalization) with one stone (PDA films) is highly desirable for developing graphene devices. And, the constructed ultrasensitive PDA/graphene photodetectors have considerable opportunities to be used in assorted photosensing areas that may not have critical requirement on operating speed.