▎ 摘　　要

NOVELTY - Preparing nitrogen-doped carbon quantum dots involves dispersing urea, sodium citrate and graphene oxide in water and mixing them into a uniform and clear liquid at room temperature. The clear solution is transferred to a polytetrafluoroethylene reactor for hydrothermal reaction, and then separated and purified. USE - Method for preparing nitrogen-doped carbon quantum dots with high fluorescence yield involves dispersing urea used in metal probes, photoelectrocatalysis and bioimaging (claimed). ADVANTAGE - The method is simple to perform, high in repeatability and economic benefit. The nitrogen-doped carbon quantum dot with high fluorescence yield of 73.89%.