Plasmonic Physical Unclonable Function Labels Based on Tricolored Silver Nanoparticles: Implications for Anticounterfeiting Applications

Physical unclonable function (PUF) labels play a key role in anticounterfeiting applications using unique inherent randomness of physical patterns. In this study, we developed a colorful plasmonic anticounterfeiting label with immense encoding capacity using randomly distributed silver nanoparticles (AgNPs) bearing three distinct sizes on the surface of the silica film deposited silicon wafer. The colloidal AgNPs can scatter different far-field scattering light in the visible wavelength region, hinging on their nanoscale size. By conversion of the colorful plasmonic PUF labels into RGB codes, a superior encoding capacity (≥87396) can be achieved. We have demonstrated that the users can identify the label authenticity using an artificial intelligence algorithm no matter the different exposure time, brightness, contrast of light source, and even small accidental cracks/scrapes applied on the colorful plasmonic PUF labels. These features provide more feasibility for the practical application of colorful plasmonic PUF anticounterfeiting labels. Overall, the developed low-cost and colorful plasmonic PUF label system with easy encoding, quick decoding process, ultra-high coding capacity, and high tolerance toward defects demonstrates a milestone for PUF labels in real-world applications.