From Graphite to Graphene Oxide and Graphene Oxide Quantum Dots.

Many methods have been reported for synthesizing graphene oxide (GO) and graphene oxide quantum dots (GOQDs) where a tedious operational procedure and long reaction time are generally required. Herein, a facile one-pot solvothermal method that allows selective synthesis of pure GO and pure GOQDs, respectively is demonstrated. What is more, the final product of either GO or differently sized GOQDs can be easily controlled by adjusting the reaction temperatures or reactant ratios, which is also feasible when enlarged to gram scale. The 2.5 nm GOQDs show excellent photoluminescence that can be utilized for bioimaging or distinctive detection of Eu and Tb from their respective mixtures with other rare earth and/or transition metal ions, at sub-ppm level.