High-Sensitivity Light Detection via Gate Tuning of Organometallic Perovskite/PCBM Bulk Heterojunctions on Ferroelectric Pb_0.92La_0.08Zr_0.52Ti_0.48O₃ Gated Graphene Field Effect Transistors

Organometallic perovskite (OMP) CH₃NH₃PbI₃ doped with [6,6]-phenyl-C₆₁-butyric acid methyl ester (PCBM) has been shown to form bulk heterojunction (OMP-PCBM BHJ) for improved charge separation. In this work, the OMP-PCBM BHJ photosensitizer is combined with graphene field effect transistors (GFETs) with a ferroelectric Pb_0.92La_0.08Zr_0.52Ti_0.48O₃ gate of high gating efficiency. A remarkable gate tunability via shifting the Fermi energy of graphene with respect to the valence band maximum and conduction band minimum of the OMP was observed, which is critical for facilitating efficient charge transfer across the OMP-PCBM BHJ/GFET interface. The combination of the high-efficiency charge separation by BHJ and charge transfer by high gate tunability leads to achievement of high photoresponsivity up to 7 × 10⁶ A/W and detectivity exceeding 7 × 10¹² Jones at 550 nm at a small gate voltage of 1.0 V. These results represent almost 2 orders of magnitude improvement over that without a gate tuning under the similar experimental condition, illustrating the importance of the interface electronic structure in optimizing the optoelectronic performance of the OMP-PCBM BHJ/GFET devices