Ultraviolet light-driven controllable doping of graphene quantum dots with tunable emission wavelength for fluorescence bio-imaging

As an important approach for tuning the emission wavelength of graphene quantum dots (GQDs), controllable doping has attracted a great deal of attentions. Here, we reported an ultraviolet light-driven doping approach for GQDs at room temperature. N-doped graphene quantum dots (N-GQDs) are obtained via the reaction in dimethylformamide under the ultraviolet radiation. The emission wavelength can be tuned from 566 to 463 nm by controlling the doping concentration. The quantum yield of N-GQDs is demonstrated to be much higher than that of most reported GQDs and increases with the increase of the doping concentration. Finally, the synthesized N-GQDs are explored for the application in fluorescence bio-imaging.