Microengineered CH₃NH₃PbI₃ Nanowire/Graphene Phototransistor for LowIntensity Light Detection at Room Temperature

The electronic performance of graphene, however, is known for its sensitivity to chemical alterations. In particular, the carrier mobility in graphene changes by orders of magnitude due to the random surface potentials imposed by the substrate and the coating layer. In order to unravel the true photodetection potential of MAPbI 3 /graphene heterostructures, a precise control of the MAPbI 3 –graphene contacts is required. To this end, we have microengineered devices where a network of MAPbI 3 nanowires (MAPbI 3 NW) has been combined with CVD-grown monolayer graphene. These phototransistors showed responsivities as high as 2.6 × 10 6 A W −1 , i.e., a value four orders of magnitude higher than existing literature reports. An MAPbI 3 nanowire/graphene phototransistor was constructed from a network of perovskite nanowires deposited by the slip-coating method reported by Horváth et al. [ 9 ]