Preparation Of N-doped Carbon Quantum Dots And Its Photoelectric Properties Research

As a kind of 0 dimensional carbon nano materials, carbon quantum dots are widely used in the fields of probes, biological imaging and optoelectronic materials because of their excellent optical and electronic properties, low toxicity and so on. Improving the luminous efficiency and exploring the large-scale preparation method is very important for the practical application of this carbon nano materials. The main work of this paper is based on the traditional carbon luminescence performance boost and new preparation methods, the improvement of the traditional carbon quantum dots and the new preparation method, on the basis of this, the properties and applications of carbon quantum dots are studied. The main work is as follows:(1) A new N-doped carbon quantum dots (NCDs) could be prepared by using glycerol as carbon source and ethylenediamine as nitrogen doped molecules through one step microwave irradiation method. The resulting NCDs probe could be applied for trace levels of direct Pb2+ recognition, and has a good linear relationship within the concentration range of 0-6.0 μM, and its detection limit is as low as 0.015 μM. Further application in real water samples shows that the carbon quantum dots have good practical application value.(2) A new N-doped carbon quantum dots (NCDs) could be prepared by using the microwave-assisted technique within 10 minutes without the need of any solvent or catalyst. The NCDs exhibited a highly sensitive electrochemical response toward dopamine (DA) in Phosphate Buffered Saline (pH=6.5). The detection limit of DA was calculated by differential pulse voltammetry (DPV) as low as 1.2 nM with a linear dynamic range of 0.05 to 8.0 μM. These results suggested that this new NCDs could be effectively used for the direct and rapid detection of trace levels of DA in human serum and urine samples.(3) A novel nanocomposite, silicon-carbon-based dots@dopamine (Si-CDs@DA) was prepared using (3-aminopropyl) triethoxysilane, glycerol and dopamine as raw materials via a rapid microwave-assisted irradiation. This type of Si-CDs@DA exhibited ultra-bright fluorescence emission (quantum yield of 12.4%) and could show response to Ag+ selectively and sensitively. Moreover, the obtained Si-CDs@DA can be further applied in sensing intracellular Ag+ and cell imaging, owing to its photostability, salt stability and low cytotoxicity. This study provides a simple and efficient approach for preparing novel Ag+ fluorescent probes, which could expand the application of carbon nanomaterials in designing related biosensors.(4) Carbon quantum dots were first obtained by using solid phase reaction method (SPRM). Compared with other methods, SPRM shows remarkable advantages on simple, rapid, and large scale CDs’ fabrication without post-treatment and solvent-free. In addition, the obtained CDs can be employed as ideal fluorescent Fe3+ probe and fluorescent ink. By taking advantage of its low-cytotoxicity, the CDs can be further applied in cell imaging successfully. This strategy offers a simple and efficient approach for preparing CDs in large-scale and lays a foundation for its further multi-purpose application.