Size sorted multicolor fluorescence graphene oxide quantum dots obtained by differential velocity centrifugation

This paper provides an effective synthesis and size sorting approach to graphene oxide quantum dots (GOQDs) with size-dependent optical properties. GOQDs were first prepared through oxidation of commercially available stacked graphene nanofibers. The as-synthesized GOQDs were then sorted into different sizes by differential velocity centrifugation. The optical properties of size-sorted GOQDs were characterized by UV-vis-NIR and photoluminescence spectroscopies. It was found that the size of the GOQDs not only shifted the fluorescence colour, but also tuned the quantum yields. Compared with the micro sized Graphene Oxide, the GOQD exhibited sharp, stable, and relatively high quantum yield fluorescence.