GRAPHENE QUANTUM DOTS WITH ITS AMINO-FUNCTIONALIZATION PREPARED BY MICROWAVE- HYDROTHERMAL METHOD

N, N-dimethyl formamide was used as the ammonia source, amino-functionalized graphene quantum dots (af-GQDs) were prepared by the microwave–solvothermal method. As confirmed by the structural analysis, the intensity of the af-GQDs (002) crystal plane diffraction peak is greater than GQDs, and the corresponding 2θ diffraction angle is right shift to 25.7°, and the interplanar spacing is reduced to 0.35 nm. Aminofunctionalization has significant influence on the crystallization degree and the layer spacing of GQDs, and the size is less than 10 nm, which is closed to zero dimension state. The af-GQDs have strong absorption in the ultraviolet region (λ≤276 nm), but it has no significant characteristic absorption peak, which fits with the semiconductor nanomaterials ultraviolet absorption spectrum. The fluorescence emission spectrum of GQDs were synthesized by this method perform excitation-dependent PL behaviors. The excitationdependent PL behaviors may be associated with electronic transitions between electronic surface state level and the LUMO energy level.