▎ 摘　　要

Graphene field effect transistor sensitized by a layer of semiconductor (sensitizer/GFET) is a device structure that is investigated extensively for ultrasensitive photodetection. Among others, organometallic perovskite semiconductor sensitizer has the advantages of long carrier lifetime and solution processable. A further step to improve the responsivity is to design a structure that can promote electron-hole separation and selective carrier trapping in the sensitizer. Here, the use of a hybrid perovskite-organic bulk heterojunction (BHJ) as the light sensitizer to achieve this goal is demonstrated. Our spectroscopy and device measurements show that the CH3NH3PbI3-PCBM BHJ/GFET device has improved charge separation yield and carrier lifetime as compared to a reference device with a CH3NH3PbI3 sensitizer only. The key to these enhancement is the presence of [6,6]-phenyl-C-61-butyric acid methyl ester (PCBM), which acts as charge separation and electron trapping sites, resulting in a 30-fold increase in the photoresponsivity. This work shows that the use of a small amount of electron or hole acceptors in the sensitizer layer can be an effective strategy for improving and tuning the photoresponsivity of sensitizer/GFET photodetectors.