Supramolecular Terbium-Threonine Chiral Emitters with Tunable Circularly Polarized Luminescence as Anticounterfeiting-Ink for Autonomous Data Encryption.

There has always been a growing demand for the development of advanced materials with dynamic properties for multi-level data encryption and anticounterfeiting. Herein, we report a facile one-pot, aqueous synthesis of a high nuclearity, luminescent, and circularly polarised luminescence (CPL)-active terbium-threonine supramolecular chiral emitters (Tb-ThrD/L-G NCs) from readily available precursors. An aqueous solution of Tb-ThrD/L-G NCs exhibits (i) 100% transparency, (ii) tunable luminescence and CPL, and (iii) pH feedback loop-controlled "on-off" of luminescence and CPL. By exploring these features, multi-level data encryption with enhanced security is demonstrated. The remarkable features of our strategy include: (i) temporal control over encryption-decryption, (ii) ability to expunge the stored information autonomously, and (iii) four distinct keys to decrypt the information, thereby offering enhanced security for the stored data. The potential of NCs as a covert anticounterfeiting ink for inkjet printing, and their excellent compatibility with commercially available polymer matrices such as polyvinyl alcohol, are also demonstrated. We believe that our rational strategy for the scalable synthesis of Tb-ThrD/L-G NCs with remarkable optical and chiroptical properties in aqueous media using readily available materials will pave the way for the facile synthesis of new lanthanide-based chiral emitters with promising applications.