Synthesis of Nanocellulose-Based Nitrogen-Doped Carbon Quantum Dots with High Fluorescence Quantum Yields for Multifunctional Applications

Carbon quantum dots (CQDs) are one of the most promising luminescent nanomaterials for anti-counterfeiting due to their excellent optical properties, low toxicity, and environmental friendliness. With the development of green chemistry, biomass carbon sources have attracted attention. Herein, nitrogen-doped carbon quantum dots (N-CQDs) are synthesized using waste corn bract nanocellulose as the carbon source and L-histidine as the nitrogen source in a simple and quick one-step microwave method. It is found that a raw material mass ratio of 1:4, a temperature of 100 degrees C, and a preparation time of 5 min are the optimum preparation conditions. The fluorescence quantum yield of N-CQDs obtained under these conditions is 32.64%. Under the excitation of light at a wavelength of 365 nm, the emission peak of N-CQDs is located at 430 nm and emits blue light. This study also provides a method to prepare fluorescent anti-counterfeiting films with excellent performance and fluorescent detection probes solely from waste biomass corn bract leaves and L-histidine.