Circularly polarized lanthanide luminescence for advanced security inks

MacKenzie, Lewis E; Pal, Robert

Abstract

Authenticating products and documents with security inks is vital to global commerce, security and health. Lanthanide complexes are widely used in luminescent security inks due to their unique and robust photophysical properties. Lanthanide complexes can also be engineered to undergo circularly polarised luminescence (CPL), which encodes chiral molecular fingerprints in luminescence spectra that cannot be decoded by conventional optical measurements. However, chiral CPL signals have not yet been exploited as an extra security layer in advanced security inks. This Review introduces CPL and related concepts that are necessary to appreciate the challenges and potential of lanthanide-based CPL-active security inks. We describe recent advances in CPL analysis and read-out technologies that have expedited CPL-active security ink applications. Further, we provide a systematic meta-analysis of strongly CPL-active EuIII, TbIII, SmIII, YbIII, CmIII, DyIII and CrIII complexes, discussing the suitability of their photophysical properties and highlighting promising candidates. We conclude by providing key recommendations for the development and advancement of the field.

Citation

MacKenzie, L. E., & Pal, R. (2021). Circularly polarized lanthanide luminescence for advanced security inks. Nature Reviews Chemistry, 5, 109-124. https://doi.org/10.1038/s41570-020-00235-4

• Journal Article Type: Article
• Acceptance Date: Oct 28, 2020
• Online Publication Date: Dec 7, 2020
• Publication Date: 2021-02
• Deposit Date: Dec 8, 2020
• Publicly Available Date: Jun 17, 2021
• Journal: Nature Reviews Chemistry
• Publisher: Nature Research
• Peer Reviewed: Peer Reviewed
• Volume: 5
• Pages: 109-124
• DOI: https://doi.org/10.1038/s41570-020-00235-4