Tailoring the edges of graphene quantum dots to establish localized π–π interactions with aromatic molecules

We report a simple route combining bottom-up and top-down strategies for the synthesis of partially ring-terminated graphene quantum dots (GQDs) employing aniline for modifying the molecular structure of GQD edges. In contrast to the GQDs synthesized without introducing ring-terminals by aniline conjugation, the photoluminescence of such partially ring-terminated GQDs can be quenched by the aromatic molecules owing to the edge-localized π–π interactions. This study provides a generalizable strategy in functionalizing GQDs towards aromatic molecule sensors, as well as important insight to the effect of edge-localized π–π interaction in perturbing the electronic structure of GQDs.