Synthesis of water-stable and highly luminescent graphite quantum dots

Highly stable and environmentally friendly nitrogen-doped graphite quantum dots consisting of similar to 12 layers of graphene, average diameter of similar to 7.3 nm, prepared by atmospheric pressure microplasma are reported to have blue emission due to surface states created by nitrogen doping (9 atomic%) and reaction with oxygen. The low-temperature synthesis method requires simple precursors in water, with no annealing or filtration, producing crystalline disc-shaped quantum dots with similar to 68% photoluminescence emission quantum yield at 420 nm excitation and that have shown stability for more than one month after the synthesis. The nitrogen doping in the quantum dots mainly occurs in graphitic core as substituted type of doping (63-67 atomic%) and the amount of doping is sufficient to create emissive states without impacting the core structure. The optical and chemical properties do not undergo serious retardation even with re-dispersion suggesting easy applicability for cellular imaging or optoelectronics.

Automated summary

Nitrogen-doped graphite quantum dots prepared by atmospheric pressure microplasma exhibit high stability and environmentally friendly properties. They emit blue light and are suitable for cellular imaging or optoelectronics applications.