Opening band gap of multi-color graphene quantum dots using D-fructose as a green precursor

Graphene was successfully isolated by Professors Andre Geim and Kostya Novoselov in 2004. Graphene has attracted considerable research importance for its distinctive properties and potential applications. In this study, low-cost and high blue, yellow, and green photoluminescent (PL) graphene quantum dots (GQDs) were synthesized with deionized water (DI) and D-fructose as precursors by the dehydration method in the presence of hydrochloric acid. Transmission electron microscopy imaging proved the changing size of the GQDs and, by nuclear magnetic resonance spectroscopy, we observed the hydrogen-functionalized GQDs. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the synthesized GQDs were determined, and an energy bandgap was obtained from optical investigations.