Mass-produced multiscale unclonable plasmonic security labels by a robotic wet-chemical system

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 475; p. 146063
• Main Authors: Yu, Dong, Liu, Zong, Hu, Chao-Kai, Shen, Yao, Li, Zhi-Jiang, Zhang, Xin-Xin, Shen, Ai-Guo
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2023
• Subjects: Physical unclonable functions; Plasmonic nanomaterials; Robotic system; Security labels; Wet chemistry; Security labels; Physical unclonable functions; Wet chemistry; Robotic system; Plasmonic nanomaterials
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2023.146063

[Display omitted] •Unclonable plasmonic security labels with multiscale random features are designed for high encoding capacity.•A robotic wet-chemical system is invented for mass-produced fabrication.•Plasmonic nanostructures and random features are variously modulated by in situ substrate growth. Plasmonic physical unclonable function (PUF) labels have been proven to be an effective anti-counterfeiting strategy, but their high tunability and multi-encoded capabilities remain to be explored for higher encoding capacity (EC). Herein, the PUF labels with high security level are prepared, which are constructed by the micro-domains of plasmonic nanostructures. The micro-domains are formed by mask-assisted ultraviolet (UV) exposure and 50 nm gold nanoparticles (Au NPs) electrostatic adsorbed on the unexposed area. And a robotic wet-chemical system is invented to modulate the in situ epitaxial growth of Au NPs by programming the growth conditions for human-free preparation and mass production. Three random processes, including mask-assisted UV photochemical reaction, electrostatic self-assembly, and in situ epitaxial growth, make sure multiscale random features. Thus, two-dimensional views with different resolutions can be obtained by three random optical imaging signals-bright field (BF), Raman imaging (RI), and dark field (DF), and the random signals will change with the modulation methods, leading to higher EC. Through analyzing the random features, a robust image authentication system is built, and the EC is calculated as 1.8 × 104966 in a 50 × 50 μm2 domain for each modulation method.