Carbon Quantum Dots Microwave And Its Application

Because the carbon quantum dots has excellent water solubility, chemical inertness, low toxicity. resistance to bleaching.etc.It has generated great attention by people.It can be used in biological imaging, detection and light catalysis.etc.But now there has a lot of synthetic methods.The experiment process is complex and time-consuming,and fluorescence quantum yield is low.So looking for a quick,simple synthesis method,and increasing the quantum yield is our effort direction in the future.Fluorescent carbon quantum dots were prepared by microwave heating method using water and pure carbon powder, one step heating method of the preparation of carbon quantum dots.It is worth noting that only use pure water as the solvent here,which is absence of acid,alkali,salt in raw materials so that effectively avoids complex experimental progress, time-consumption,expensive raw materials or rigorous experimental conditions. Quantum dot size in this way is about2-3nm,has the very good single dispersion and solubility in water.Under the excitation of visible light at230nm and310nm can emit435nm light,and thefluorecence emission intensity is stronger, its fluorescent quantum yield is7.8%. After using polyethylene glycol as passivation reagents. Heating nano carbon powder and polyethylene glycol (550and5000), the molecular weight of mixed aqueous solution, the preparation of carbon particle size changed a little, carbon quantum dots under the excitation of light can emit438nm blue light, but the fluorescence emission intensity is low.All kinds of heavy metal ions were studied in the preparation of carbon dot of fluorenscence emission. The experimental results is concluded that the metal ions, without changing the point of the carbon fluorescent emission spectrum shap,but for fluorescence emission intensity of carbon points have different degrees of quenching effect.The Fe3+fluorescence quenching effect is most obvious. Greatly reduces the fluorescence emission intensity of carbon points,The quenching mechanism for charge quenching, or dynamic quenching.