Fabrication of reduced graphene oxide hybrid materials that exhibit strong fluorescence

Fluorescent graphene-based materials have been prepared by a facile ion exchange route comprising the reaction of carboxylated, reduced graphene oxide (c-RGO) with fluorescent anthracene-modified imidazolium salts in water-ethanol solution. The resulting reduced graphene oxide hybrid materials emit strong blue light at 392, 414 and 438 nm and maintain a relatively high quantum yield (QY, 0.29), as electron and energy transfer between the anthracene moieties and the graphene plane is blocked by the imidazolium moiety. In contrast, physical mixing of the imidazolium salt with non-carboxylated reduced graphene oxide (n-RGO) affords a material that exhibits negligible fluorescence due to direct pi-pi stacking interactions between the n-RGO plane and the anthracene moieties.