Preparation of coal-based carbon quantum dots and their fluorescence properties

[Display omitted] •Carbon quantum dots were prepared from low-rank coal.•The mechanism of generating CQDs consists of an aromatic cluster thickening process resulting from the Scholl reaction.•Modification of carbon quantum dots with polyethylene glycol (PEG) will increase the fluorescence quantum yield.•Carbon quantum dots prepare electrospinning polyvinyl alcohol films with fluorescent properties. In the field of life sciences, cellular movements play a significant role in influencing the activities of organisms. Current methodologies have limitations in the monitoring of cell recognition, biological macromolecule localization, cell labeling, migration, and biosensors. Although metal–semiconductor quantum dots are commonly used, they may pose toxicity risks to the lungs and kidneys. On the other hand, carbon quantum dots possess the unique optoelectronic properties of traditional quantum dots while exhibiting low toxicity, good biocompatibility, excellent photostability, and abundant raw material sources. In this research, carbon quantum dots were synthesized using the nitric acid oxidation method. The study investigated the effects of temperature, time, and the type of low-rank coal on the synthesis of carbon quantum dots. The structure and properties of the carbon quantum dots, specifically their fluorescence characteristics, were thoroughly analyzed. The proposed synthesis approach includes the nitration of coal macromolecules and the thickening of aromatic clusters through the Scholl reaction, leading to enhanced fluorescence quantum efficiency. The findings of this study indicate that the carbon quantum dots produced through this method demonstrate a high fluorescence quantum yield, making them ideal fluorescent agents for material preparation and offering potential applications in the field of life sciences.