Solvothermal method to prepare graphene quantum dots by hydrogen peroxide

• Using of hydrogen peroxide and expanded graphite as raw material decrease the preparation cost of GQDs greatly.
• Evaporation/redissolution and filtration process provide high purity of GQDs and no need of dialysis saves much time.
• The GQDs prepared by this method have a strong blue emission at 15% quantum yield.

Graphene quantum dots (GQDs) have been synthesized by different chemical methods in recent years. For conventional chemical methods, it is inevitable to introduce a large amount of impurities in the preparation process. Long time of dialysis process increases the time cost extremely. Herein, we report a one-step solvothermal method for synthesizing GQDs with the application of hydrogen peroxide in N, N-Dimethylformamide (DMF) environment, which completely avoids the use of concentrated sulphuric acid and nitric acid to treat raw material and introduces no impurity in whole preparation process simultaneously for the first time. Pure GQDs can be obtained after evaporation/redissolution and filtration process with a strong blue emission at 15% quantum yield. This solvothermal method, not requiring dialysis process and complicated equipments, exhibits simple, eco-friendly and low time-cost properties. Besides high quantum yields, the as-prepared GQDs also show good photoluminescence stability in different pH conditions. The optical properties, morphology and structure of GQDs were studied by various equipments, implying potential application in biomedical fields and electronic device.

GQDs with no impurities were prepared by reacting expanded graphite with H2O2 under solvothermal conditions. No need for dialysis process decrease the time cost greatly. The as-prepared GQDs show a high quantum yield at 15%, and perform good optical stability in different pH conditions.Figure optionsDownload high-quality image (167 K)Download as PowerPoint slide