Forster Resonance Energy Transfer Mediated Charge Separation in Plasmonic 2D/1D Hybrid Heterojunctions of Ag-C3N4/ZnO for Enhanced Photodetection

We report on the events of Forster resonance energy transfer (FRET) and direct transfer (DT) of electrons in two-dimensional graphitic carbon nitride (g-C3N4) nanosheets-based plasmonic hybrid heterojunctions of Ag-C3N4/ZnO. The occurrence of FRET has been understood from the quenching of emission and lowering of luminescence decay time of the hybrid samples. Using the measured lifetime, the FRET efficiency has been estimated to be similar to 61% at a concentration of 5 mM of Ag nanoparticles. It has been found that the FRET process triggers the surface plasmon oscillation in metallic Ag nanoparticles. In turn, the hot electron injection from plasmonic Ag to C3N4 results in the near-UV emission in g-C3N4. The attachment of zinc oxide (ZnO) nanorods with the hybrid nanosheets has led to an efficient charge separation due to the formation of type II band alignment. The FRET induced excitation of electrons in hybrid nanosheets and their subsequent transfer to nanorods has led to the improvement in photoconductivity response of Ag-C3N4/ZnO hybrid heterojunctions.