Manufacturing unclonable anti-counterfeiting labels using robust diamond microparticles on heterogeneous substrates

Abstract The growing prevalence of counterfeit products worldwide poses serious threats to economic security and human health. Developing advanced encryption materials with physical unclonable functions offers an attractive defense against counterfeiting. Here, we have successfully developed multimodal, dynamic and unclonable anti-counterfeiting labels based on high-quality diamond microparticles containing silicon-vacancy (SiV) centers. These chaotic microparticles were heterogeneously grown on silicon substrate by chemical vapor deposition, facilitating scalable and massive fabrication at low cost. Due to the non-deterministic nature of this growth method, the intrinsically unclonable function has been introduced by the randomized features of each individual particle. In particular, the extremely stable signals of SiV photoluminescence (PL) and light scattering from diamond microparticles are shown to enable high-capacity optical encryption. Moreover, time-dependent encryption has been achieved by dynamically modulating the SiV PL signals and/or controlling packed patterns of diamond microparticles via post air oxidation. Exploiting the robustness of diamond, the developed diamond-based labels exhibit ultrahigh stability in different extreme application scenarios, including harsh chemical environments, high temperature, mechanical abrasion, and UV light irradiation. Our proposed system, with its extreme randomness, multimode and dynamic encryption capability and outstanding robustness, can be practically applied immediately as anti-counterfeiting labels in diverse fields.