Performance of zinc oxide quantum dots coated paper and application of fluorescent anti-counterfeiting

Fluorescent anti-counterfeiting is one of the most widely used anti-counterfeiting technologies at present. The demand to develop new anti-counterfeiting materials and technology is more and more urgent. Zinc oxide quantum dots (ZnO QDs) have superior fluorescent properties under ultraviolet light, making them a suitable replacement for traditional phosphors for anti-counterfeiting printing, which is environmentally friendly and meets the needs of sustainable development. In this paper, water-soluble ZnO QDs with an average particle size of 5.64 nm were prepared. Paper coated by ZnO QDs was obtained after ultrasonic treatment, which could emit bright yellow fluorescence when excited by ultraviolet light. As the concentration of ultrasonic solution is increased, the loading amount of ZnO QDs on the coated paper increased gradually, reaching the maximum when the concentration is increased to ${1}\;{\rm mol}\;{{\rm L}^{- 1}}$, which then does not change with an increase in concentration. The fluorescent intensity of the coated paper was consistent with the changing trend of the loading amount. The coated paper has excellent optical stability, is easy to recycle, and provides simple identification of authenticity by ultraviolet light and anti-copy functionality. Their application in packaging and printing is of great significance to the development of complex, concealed and non-repeatable anti-counterfeiting technology.