Photochemical Synthesis of Dendritic Silver Nano-particles for Anti-counterfeiting

High-trust anti-counterfeit methodologies that tag only genuine goods are in high demand globally in manufacturing and security. However, prevalent tagging methods often face challenges in manufacturing cost, structural reliability, and simplifying readout procedures. Here we report a one-pot photochemical synthetic method to produce large quantities of dendritic silver nano-particles (AgNPs) within 20 minutes and under ambient conditions, promising for large-scale manufacturing of physical taggants. By tuning the experimental conditions, such as the UV illumination and the concentration of silver-reducing agent, poly(allylamine), we demonstrate the feasibility of creating unique dendritic AgNPs with distinctive morphological characteristics. Our investigation illustrates the significant impact of the interplay between silver nucleation and growth that is critical in producing the dendritic AgNP taggants with controlled shape and sizes. Importantly, we verify by simple optical imaging and image analysis that all the dendrites possess a singular set of minutiae that lead to a vast number of unclonable features, suitable for anti-counterfeiting labels.