Enhancement of the Anti-Stokes Fluorescence of Hollow Spherical Carbon Nitride Nanostructures by High Intensity Green Laser

Fluorescence spectra of graphitic (g-C3N4) and spherical (s-C3N4) modifications of carbon nitride were measured as a function of green pulsed (6 ns-pulse) laser intensity. It was found that the intensity of the laser increases the maximum of the fluorescence shifts towards the anti-Stokes side of the fluorescence for s-C3N4 spherical nanoparticles. This phenomenon was not observed for g-C3N4 particles. The maximum of the anti-Stokes fluorescence in s-C3N4 nanoparticles was observed at 480 nm. The ratio of the intensity of the anti-Stokes peak (centered at 480 nm) to that of the Stokes peak (centered at 582 nm) was measured to be I-484/582 = 6.4 x 10(-3) at a low level of intensity (5 mW) of a green pulsed laser, whereas it rose to I-484/582 = 2.27 with a high level of laser intensity (1500 mW).

Automated summary

The fluorescence spectra of graphitic and spherical modifications of carbon nitride were measured with green pulsed laser intensity. It was found that the fluorescence peak of spherical nanoparticles shifted towards the anti-Stokes side with increasing laser intensity, with no such observation in the case of graphitic particles. The intensity ratio of the anti-Stokes peak to the Stokes peak increased with higher laser intensity.