Light Irradiation-Triggered Multicolor Luminescence via Multi-Coordinated Sites for Multilevel Luminescent Encryption

Nowadays, luminescent information remains limited to multicolor static or single-color dynamic change driven by high-energy UV, still facing a significant challenge in achieving multilevel luminescent encryption. Here, a visible light irradiation-triggered dynamic multicolor luminescent material of Na 2 Ba 6 (Si 2 O 7 )(SiO 4 ) 2 :Eu with multi-coordinated sites is reported. The system possesses three emission centers of red (Eu 3+ ), green [Eu 2+ (2)], and blue [Eu 2+ (1)], and can realize a large luminescence contrast (Δ R t = 96.6% at 444 nm) by 405 nm irradiation-induced oxidation reactions. By adjusting the excitation wavelengths or light irradiation time, the luminescence color and contrast can be dynamically tuned. The unique optical tunable luminescence properties endow them with potential applications in multilevel anticounterfeiting and combined information encryption. The results provide a novel approach for realizing multicolor luminescence modulation under a light field, greatly improving the security level of encrypted information.