Synergistic effect of graphene enhances the responsivity of hybrid perovskite photodetector

Organometal halide perovskite has aroused extensive interest due to its high absorption coefficient and flexible synthetic strategy for fabricating sensitive and low-cost photodetectors. Nevertheless, obtaining large and ordered orientation perovskite grain, developing enhanced optical absorption, and restraining defect states of grain boundaries are still open and challenging processes. Here, we report a flexible hierarchical architecture to promote grain growth and absorption strength. Therein, graphene and its derivatives are adopted to produce enlarged grain via an in situ hot-casting scheme. The surface plasmon resonance effect of highly conductive reduced graphene oxide-silver (Ag-rGO) nanoparticles is introduced to improve perovskite absorbance, enhancing responsivity by nearly four orders of magnitude to 13 AW−1. Meanwhile, density functional theory calculations and finite-difference time-domain analysis confirm the absorption enhancement and effective separation of the photogenerated carriers. This work elucidates the synergistic effect of graphene based on strain template and surface plasmon resonance in fabricating high-responsivity photodetectors.