▎ 摘　　要

NOVELTY - Preparing bimodal fluorescence emitting graphene quantum dot comprises inserting the carbon source working electrode, counter electrode and reference electrode into the electrolyte, adjusting and maintaining the temperature of the electrolyte to 50-80degrees Celsius, performing cyclic voltammetry to obtain a solution dispersed with bimodal fluorescence emission graphene quantum dots, filtering, dialyzing, and freeze-drying to obtain water-soluble bimodal fluorescence emitting graphene quantum dots. USE - The quantum dot is useful in a ratiometric fluorescent probe (claimed). ADVANTAGE - The method: prepares quantum dots by electrochemical oxidation under thermal assistance; is environmentally friendly, simple and safe; and has potential for large-scale production. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) a bimodal fluorescence emitting graphene quantum dot prepared by the above-mentioned method, where the average particle size of the quantum dot is 1.4-2.1 nm; (2) adjusting the average particle size of bimodal fluorescence emitting graphene quantum dot, comprising adjusting the average particle size of the bimodal fluorescence emission graphene quantum dots by adjusting the temperature of the electrolyte, where the average particle size of the bimodal fluorescence emission graphene quantum dots decreases as the temperature of the electrolyte increases; and (3) adjusting the fluorescence emission peak of bimodal fluorescence emitting graphene quantum dot, comprising adjusting the temperature of the electrolyte to adjust the fluorescence emission peak of the bimodal fluorescence emitting graphene quantum dots, where with the increase of the temperature of the electrolyte, the distance between the two fluorescence emission peaks of the bimodal fluorescence emission graphene quantum dots under excitation at 300 nm at room temperature increases, and the intensity ratio of the fluorescence emission peak with larger wavelength relative to the fluorescence emission peak with smaller wavelength increases.