▎ 摘　　要

NOVELTY - Graphene ink is claimed. The graphene ink is prepared by efficiently dispersing graphene with riboflavin sodium phosphate to obtain graphene dispersion liquid and adding ethanol to obtain final product, where the final concentration of riboflavin sodium phosphate in graphene dispersion liquid is 0.05-0.5 mg/ml and the ratio of ethanol and graphene dispersion liquid is 1:0.1-50. USE - The graphene ink is useful for printing flexible devices without high temperature post-treatment (claimed). ADVANTAGE - The graphene ink: utilizes riboflavin sodium phosphate molecule, which has a large conjugated carbon skeleton structure (dimethylisooxopyrimidine ring) and can generate strong adsorption with the graphene sidewall, and ensures the graphene is efficiently dispersed by ultrasound-assisted sodium riboflavin phosphate; and has extremely low surfactant content and high dispersion stability. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of graphene ink, comprising (1) adding graphene powder into deionized water to obtain mixed solution, performing ultrasonically treatment to obtain graphene dispersion liquid, where the ultrasonic treatment of mixed solution is performed at less than 30℃ for 0.5-20 hours; the ultrasonic power has a gradient power from high to low, and power range of 30-700 W; adding riboflavin sodium phosphate aqueous solution for many times during the graphene ultrasonic process to prepare a graphene dispersion having concentration of 1-10mg/ml and storing in a brown reagent bottle, the concentration of riboflavin sodium phosphate aqueous solution is 0.1-1 mg/ml, and (2) adding ethanol into the graphene dispersion liquid to obtain final product the ratio of ethanol and graphene dispersion liquid is 1:0.1-50.