Synthesis Of Novel Fluorescent Carbon Dots Via A One-step Hydrothermal Treatment And The Applications Research

As a new important member of the carbon nanomaterial family, fluorescent carbon dots (CDs) had received increasing attentions in recent years. Fluorescent carbon dots, named carbon nanodots, carbon quantum dots and cabon nanocrystal at the same time, were monodisperse carbon nano-functional materials with10nm below in diameter and qusi-spherical in shape geometry. CDs, with similar semiconductor quantum effect and upconversion property, showed excellent potentials in environmental detecting, photo catalyst, cell marking and bioimaging, solar cell catalyst, etc. Compared with fluorescent organic dyes and quantum dots, CDs showed good water-solubility, biocompatibility, resistance to photobleaching, green synthesis process, low-toxicity and synthesis methods were simple and low-cost. Owing to these excellent properties, CDs had become a hot research point as a desirable candidate for replacing quantum dots.Many researchers had made much progress in synthesis methods, performance optimization and broadening applications of CDs. It was found that CDs with high fluorescent quantum yields (QYs) could be obtained by doping nitrogen and sulfur into carbon dots. In this work, new carbon source were used to synthesis CDs via one-step hydro thermal treatment. Based on the interactions between the obtained CDs and metal ions, a method was found for detecting Fe3+and H2O2. Content is as follows:(1) Glutathione (GSH) as the only carbon source, hydrothermal treatment was used to prepare CDs. We optimized the reaction time and temperature. The obtained glutathione carbon dots (CGSH dots) were with plenty of functional groups existed on the surface. CGSH dots were with good water solubility and showed good fluorescent stability even in the conditions of various concentrations of NaCl. However, the quantum yields (QYs) of CCSH dots was low. The interactions between CGSH dots and metal ions were explored, the results showed the fluorescence of CGSH dots could be quenched by Fe3+and Hg2+(2) To obtain CDs with high QYs, citric acid (CA) and GSH were used together to produce glutathione-citric acid carbon dots (CGSH-CA dots) through a one-step hydrothermal treatment. Compared with the as-prepared CGSH dots, the CGSH-CA dots exhibited high QYs and also had plenty of functional groups such as carboxyl group and thiol group. The CGSH-CA dots were water-soluble, photostable in the conditions of various concentrations of NaCl. The interactions between CGSH-CA dots and metal ions were explored, the fluorescence quenching was observed especially when Fe3+existed. Based on this, a method was found for detecting Fe3+and H2O2. Owing to their excellent fluorescence properties, CGSH-CA dots would be a desirable candidate both in cell imaging and environmental detecting.