▎ 摘　　要

NOVELTY - Fluorescence-adjustable nitrogen-doped graphene quantum dot preparation involves dissolving 42 mg citric acid in 20 ml absolute ethanol to obtain precursor, and adding 70 mg o-phenylenediamine, 70 mg m-phenylenediamine and 70 mg p-phenylenediamine in 20 ml absolute ethanol to obtain another precursor. The obtained precursors are respectively mixed in a volume ratio of 1:1 to obtain hydrothermal reaction precursors. The obtained precursors and absolute ethanol are mixed in a volume ratio of 1:1 to obtain hydrothermal reaction precursor, and then transferred in 50 ml polytetrafluorohydrothermal reaction chamber for sonication for 30 minutes at 180 degrees C for 12 hours for hydrothermal reaction, and then cooled at room temperature to obtain nitrogen-doped graphene quantum dots. The quantum dots are diluted with absolute ethanol and irradiated with 365 nm ultraviolet lamp to obtain green, purple, yellow, blue-green and orange-red respectively. USE - Method for preparing fluorescence-adjustable nitrogen-doped graphene quantum dot used in supercapacitor, photoelectric or bio-image. ADVANTAGE - The method prepares the fluorescence-adjustable nitrogen-doped graphene quantum dot in a simple, cost-effective and eco-friendly manner with continuous adjustable characteristic in the range of 430-580 nm, and wide application prospects. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic fluorescence emission spectrum of the prepared fluorescence-adjustable nitrogen-doped graphene quantum dot.