Unclonable Chameleon Security Inks

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Project BackgroundLanthanide complexes are widely used in luminescent security inks due to their unique and robust photo-physical properties and they can also easily be engineered to undergo circularly polarised luminescence (CPL). However, chiral CPL signals have not yet been exploited as means in advanced security inks. Until our recent break-through in CPL measurement technology that enables rapid, high-throughput, security ink verification, the technology used to measure CPL has been somewhat stagnant. Project DescriptionThe synthetic aspect of this project is dedicated to develop blended polymer encapsulated organic emitters and chiral Ln(III)complexes to create multi-layered unclonable QR code patterns. Novel CPL-active Ln(III) complexes with cumulative expertise based strategies to maximise gem and increase CPB (CPL brightness) will be synthesized as part of the project. Using a commercially available polymer matrix that is already part or will be suitable to be incorporated into modern 'plastic' banknotes as a transparent layer a lithographically etched chiral separator can be embedded into the banknote alongside the luminescent dye formula. Therefore, using a handheld time resolved detector, also developed as part of this project using a novel polarized Thor labs camera, and the 'secret etched polarizer' (the structure of the Big Ben is perfect) in combination with a unique dye mixture formula can result in a unique fingerprint tri-colour security dye encoding 3 chiroptical QR codes in one. A simple fold over of this separator unit onto the UV illuminated banknote will result in colour change of the security dye that can further be changed to a third hidden colour by time gating the red Europium component (unique chiral/spectral fingerprint and ms lifetime) separating it from the short lived (ns) organic green or blue fluorophores. These combined are unprecedented, resulting in 5 tiers of unclonable hidden (invisible to the naked eye) security feature. This project therefore combines polymer science, lithography and dye formulation of organic and chiral lanthanide emitters rendering it to be a truly multidisciplinary research project.Our newly developed all solid-state (SS-)CPL spectrometer is a paradigm shift in CPL spectroscopy and allows the global research community and the public to harness the so far uncharted benefits of CPL. This renders this unique platform extremely desirable by any third party interested in authentication and protection of global commerce.Once a suitable dye, combining organic short-lived fluorescence green/blue emitters with chiral (CPL active) red/green (Terbium/Europium) long-lived emitters is formulated and embedded into transparent polymer matrix as a thin layer the possibilities are endless to create infinite number of 5 layer security QR codes and authentication stamps/logos allowing the next chapter of intelligent unclonable security authentication to be written.