A Novel One-Step Approach to Synthesize Fluorescent Carbon Nanoparticles

Fluorescent carbon nanoparticles (CNPs) were prepared directly by a simple hydrothermal method by using L-ascorbic acid as a carbon source. The synthesized CNPs with higher photoluminescence efficiencies (6.79%) are monodisperse, and their diameter is about 2.0 nm. In contrast to previous methods, for this one-step process, neither strong acid treatment nor further surface modification is necessary. Aqueous solutions of the CNPs are stable at room temperature for at least half a year. In particular, the fluorescence of the CNPs does not change over a wide pH range and even in solvents with strong ionic strengths (e.g. 2.M NaCl).