The influence of combination mode on the structure and properties of graphene quantum dot-porphyrin composites.

As a rising star in the family of fluorescent material, graphene quantum dots (GQDs) have attracted great attention because of their excellent properties such as high photostability against photobleaching and blinking, biocompatibility, and low toxicity. Herein, strongly fluorescent GQDs have been prepared by one-step solvothermal method. Then three kinds of GQDs-porphyrin composites were assembled by means of noncovalent interaction. It was found that the functional groups on the peripheries of the porphyrin were important on the combination mode of porphyrin and GQDs. The fluorescence of GQDs was quenched in the presence of the porphyrin. The suggested quenching mechanism is through Förster resonance energy transfer (FRET). Tetrasodium-meso-tetra(4-sulfonatophenyl) porphine dodecahydrate (NaTSPP) was easy to react with GQDs and flat on the GQDs due to the strong hydrogen bond and π-π interaction. The photoelectronic activity of the GQDs-NaTSPP composite was higher than those of the other two GQDs-porphyrin composites. These results provided some hints for how to adjust the properties of the GQDs-porphyrin composites by modifying the combination mode between porphyrins and GQDs. These novel GQDs-porphyrin composites hold promise for various optical and luminescence-based applications.