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Updated: May 11, 2026
Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities
Published on: July 24, 2015
Large scale preparation of graphene quantum dots from graphite with tunable fluorescence properties
Yiqing Sun1, Shiqi Wang, Chun Li
1Department of Chemistry and Key Laboratory of Organic Phosphorus and Chemical Biology of Chinese Education Commission, Tsinghua University, Beijing 100084, People's Republic of China.
Abstract:
We report an improved Hummers method for synthesizing graphene quantum dots (GQDs) by directly oxidizing and etching graphite powders. The yield of GQDs is as high as 63 ± 7% (by weight, wt%), suggesting this technique is suitable for producing GQDs on a large scale. The GQDs are nanocrystals with lateral dimensions in the range of 2-4 nm and an average thickness of around 1.3 nm. The emission peaks of as-prepared GQDs can be tuned in the range of 440 to 510 nm by varying the reaction conditions. Their fluorescence quantum yields were tested to be around 1%, which could be further increased to about 3% by hydrothermal treatment. These GQDs have low cytotoxicity and excellent biocompatibility, indicating that they are promising for biological applications.
