Cavity induced fluorescence enhancement of graphitic carbon nitride submicron flakes

Graphitic carbon nitride (g-C3N4), which is structurally analogous to graphene, shows excellent fluorescent yield. Sharp ripple structure is observed in the fluorescence spectra of g-C3N4 flakes grafted on the surface of single polymethyl methacrylate (PMMA) microspheres. The intensities and the number of modes of these structures nonlinearly vary with the sizeof micro-cavity and the coupled power. Theoretical simulations carried out with the help of Mie theory show that the ripple structure is dueto modulation of the fluorescenceby the whispering gallery modes (WGMs) of the spherical microcavity.