Graphene quantum dots via ion modification for improving photoluminescence stability in aqueous solution with heavy metal ions

•We have developed a photoluminescence maintenance strategy that GQDs are modified by scandium ions (Sc@GQDs).•The prepared Sc@GQDs own better fluorescent properties than pristine GQDs in aqueous solution containing heavy metal ions.•This strategy possesses the universality for other metal ions, such as Ga3+ and Al3+.•Sc@GQDs show great potential in the applications of fluorescent flexible device and fluorescent ink.