Solvothermal Synthesis and Inkjet Printing of Carbon Quantum Dots

Fluorescent carbon quantum dots (CQDs) have been widely used as anti-counterfeiting materials due to their excellent optical properties, but the in-depth studies on the effects of solvent and ink properties on the inkjet printing still very few. Using L-ascorbic acid as a carbon source, CQDs were prepared by the solvothermal method and dissolved in different solvents. Then, the structures, morphologies, optical properties were characterized by Fourier transform infrared spectroscopy (FTIR), UV-vis and fluorescence spectroscopic, and transmission electron microscope (TEM) in detail. The results show that there are many hydrophilic groups on the surface of the CQDs, and the luminescence mechanism is mainly based on the defective state of the oxygen surface. The solubility of the CQDs in a polar solvent is good, and it has good fluorescence emission performance, which is the result of the interaction between the polarity of the solvent and hydrogen bond. At the same time, the CQDs ink prepared in this experiment can be printed on the bond paper by inkjet to form a bright blue fluorescent pattern.