Supramolecular coordination modulating organic room temperature phosphorescence for multi-level information encryption

Organic room temperature phosphorescent (RTP) materials have emerged as a prominent research area due to their unique luminescent properties and wide applications. However, it remains a great challenge to realize a distinct RTP modulation by one stimulus, although it is highly desirable for developing high-level information encryption. Herein, we fabricate two distinct RTP films by incorporating terpyridine (Tpy) derivatives with a carboxylic or amine group into polyvinyl alcohol (PVA), exhibiting entirely different optical responses upon the introduction of dynamic lanthanide (Ln) coordination. The RTP film fabricated by carboxylic group-functionalized Tpy derivative shows significant changes in fluorescence and RTP emissions upon the addition of Ln³⁺ due to efficient triplet-to-singlet Förster resonance energy transfer (TS-FRET). On the contrary, the RTP film prepared by amine group-functionalized Tpy derivative demonstrates almost unchanged optical properties after introducing Ln³⁺. Encouraged by such a distinct Ln³⁺ modulation, multi-level information encryption is well demonstrated with a largely improved security level. This study not only contributes to the development of modulable RTP materials but also promotes the advancement of high-level information encryption.