Synthesis of high-performance carbon dots from laurel leaves and their application in anti-counterfeit ink

Green-emitting carbon dots (G-CDs) with high quantum yield were successfully synthesized through a one-step bottom-up approach, utilizing laurel leaves as the carbon precursor, o-phenylenediamine (OPD) as the nitrogen source, and N,N-dimethylacetamide (DMAC) as the solvent. Structural characterizations unveiled the presence of abundant nitrogen-containing functional groups on the surface of G-CDs, significantly influencing their luminescent properties. The excitation and emission wavelengths of G-CDs were determined to be 467 nm and 508 nm, respectively, with a quantum yield of up to 49.9 %. Moreover, the emissions of G-CDs were found to be dependent on the excitation wavelength, suggesting a potential correlation between luminescence and particle size. Notably, the stability assessment demonstrated excellent salt resistance and strong photostability of the G-CDs. A brief discussion on the practical application of G-CDs in anti-counterfeit fluorescent ink highlighted their potential in this filed. This study presents a green synthesis strategy for producing high-performance carbon dots, reducing reliance on chemical reagents, lowering synthesis costs, and mitigating environmental pollution.