Unclonable fluorescence behaviors of perovskite quantum dots/chaotic metasurfaces hybrid nanostructures for versatile security primitive

Quantum dots (QDs) and metasurfaces show attractive performances for security applications such as anticounterfeiting, authentication and information encryption. They are usually employed as anticounterfeiting inks or structural colors and their patterns are fabricated using reproducible deterministic process, which is clonable and can be faked by counterfeiters. Herein, fluorescence pattern and lifetime of perovskite QDs are manipulated by chaotic metasurfaces to produce unclonable fluorescent speckles at the optical diffraction limit, resulting in a spatial/temporal dual-mode physical unclonable function (PUF). Radiation-chemical reactions of polymethylmethacrylate (PMMA) under ion beam etching are employed to fabricate the chaotic metasurfaces in large areas and coupled with randomly distributed perovskite QDs, providing a low-cost way to prepare the unclonable fluorescent anticounterfeiting labels. An enormous encoding capacity of over 2^156,250 is obtained with a tiny PUF about one hundred micrometers across. A high-security mutual authentication scheme for Internet of Things (IoT) is proposed based on a pair of the PUFs, in which no private key needs to be digitally stored and more than 26 Tbit/cm² binary public keys are generated. Such PUF open up a new prospect for the utilization of perovskite QDs and metasurfaces as an advanced security primitive at the nanoscale.