▎ 摘　　要

NOVELTY - Preparing ion-functionalized graphene quantum dot comprises mixing graphene quantum dot solution and functional agent for functionalization to obtain the ion-functionalized graphene quantum dots, where the functional agent includes functional elements, functionalizing elements includes rare earth elements and/or group IIIA elements. USE - The ion-functionalized graphene quantum dot is useful in detecting heavy metal ion (claimed), ADVANTAGE - The method: maintains fluorescence stability in the environment containing heavy metal ions; and provides strategy for maintaining the luminescence stability of graphene quantum dots. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for ion-functionalized graphene quantum dots prepared by above mentioned method.