Silica-covered Au nanoresonators for fluorescence modulating of a graphene quantum dot

We synthesize Au@SiO₂ composite particles with a core-shell structure, and utilize the Au@SiO₂ nanoparticles to modulate the fluorescence emission of the graphene quantum dot (GQD) through varying the silica shell thickness. The silica shell thickness can be easily controlled by varying the coating time. After silica coating, we investigate the influence of the silica thickness on the fluorescence emission of the GQD and find that the fluorescence property of the GQD can be changed as expected by varying the thickness of the silica shell. We propose an optimized coating time for the silica shell under the interaction of fluorescence quenching and enhancement.