▎ 摘　　要

NOVELTY - Preparing single-layer graphene quantum dots comprises (a) adding the saturated ethanol solution of m-phenylenediamine to sodium hydroxide aqueous solution, slowly injecting part of the saturated acetaldehyde aqueous solution into the solution, mixing well, performing aminoaldehyde condensation reaction to obtain a brown-yellow reaction liquid, (b) adding 1 M sodium hydroxide aqueous solution to the reaction solution in the previous step, nucleating to obtain a suspension with black particle, (c) placing the obtained solution into a centrifuge tube, removing the supernatant by high-speed centrifugation to obtain a black precipitate at the bottom and (d) adding acetic acid or hydrochloric acid to the black precipitate, where the black precipitate gradually dissolves to obtain a clear brown solution, adjusting the solution to neutral, placing in a freeze dryer and freezing to obtain single-layer graphene quantum dot. USE - The method is useful for preparing single-layer graphene quantum dots. ADVANTAGE - The dot has good stability, low biological toxicity and good photodynamic property. DETAILED DESCRIPTION - Preparing single-layer graphene quantum dots with good photodynamic property comprises (a) adding the saturated ethanol solution of m-phenylenediamine to 0.2 M sodium hydroxide aqueous solution, slowly injecting part of the saturated acetaldehyde aqueous solution into the solution, mixing well, allowing to stand for 4-16 hours for aminoaldehyde condensation reaction to obtain a brown-yellow reaction liquid, (b) adding 1 M sodium hydroxide aqueous solution to the reaction solution in the previous step, allowing to stand for 4-16 hours to further undergo ammonia aldehyde condensation reaction and nucleating to obtain a suspension with black particle, (c) placing the obtained solution into a centrifuge tube, removing the supernatant by high-speed centrifugation to obtain a black precipitate at the bottom and (d) adding acetic acid or hydrochloric acid to the black precipitate, where the black precipitate gradually dissolves to obtain a clear brown solution, adjusting the solution to neutral, i.e. the solution is the dispersed single-layer graphene quantum dot solution, placing in a freeze dryer and freezing for 12 hours to obtain single-layer graphene quantum dot.