Fluorescence behavior of nanoconjugates of graphene quantum dots and zinc phthalocyanines

• Graphene quantum dots (GQDs) were linked to zinc phthalocyanines via covalent and non-covalent modes.
• GQDs fluorescence was quenched in the presence of the ZnPc derivatives.
• The conjugates showed stimulated emission from the phthalocyanines.

Graphene quantum dots (GQDs) and zinc phthalocyanines interactions in different modes (covalent and non-covalent) are reported in this study. GQDs were covalently attached to the following complexes: zinc tetraamino phthalocyanine (ZnTAPc) via amide coupling, zinc tetracarboxyphenoxy Pc (ZnTCPPc) (π–π interaction) and cationic zinc tetrapyridiloxy Pc (ZnTmPyPc) (ionic interaction). GQDs fluorescence was quenched in the presence of the ZnPc derivatives. The nanoensembles of GQDs–ZnPcs showed stimulated emissions of the ZnPcs. The suggested quenching mechanism is through Förster resonance energy transfer (FRET). These novel nanoensembles hold promise for various optical and luminescence based applications.