ABSTRACT
A ball milling method which is green with simple-manipulation and low-cost was used to prepare graphene as precursor for graphene quantum dots (GQDs) synthesis.Subsequently, GQDs with good dispersibility, uniform size distribution, average diameter of (4.80 ± 0.20) nm and 1-3 layers were prepared by one-step hydrothermal method.The morphology, structure and optical properties of the GQDs were characterized by high-resolution transmission electron microscopy (HRTEM), atomic force microscope (AFM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), UV-Vis absorption and fluorescence spectroscopy.Furthermore, the GQDs were used in label-free and specific detection of ferric ion (Fe.3+) with broad linear ranges of 2.0×10.-6-7.0×10.-4 mol/L and low detection limit of 1.8 × 10.6 mol/L (S/N=3).The possible mechanism was also discussed and the application of GQDs for Fe.3+ detection in tap water was demonstrated.Finally, based on their low cytotoxicity and excellent biocompatibility, the as-prepared GQDs were successfully applied to efficient cell imaging.This work provides a new way for preparation of carbon-based nanomaterials and build a foundation for deepening applications of GQDs in bio-/chem-analysis, bioimaging, etc.