Achieving Multimodal Emission in Zn₄B₆O₁₃:Tb³⁺,Yb³⁺ for Information Encryption and Anti-counterfeiting

With the rapid development of technology, information security has always been considered a major challenge. In this work, the excellent combination of persistent luminescence, photoluminescence, up-conversion luminescence, and thermo-luminescence in a particular material Zn₄B₆O₁₃:Tb³⁺,Yb³⁺ synthesized via a solid-state reaction is reported, which can be used for the information encryption and anti-counterfeiting. Tb³⁺ ions were chosen as the emitting centers for multimodal emissions, and Yb³⁺ codoping can be used as electron traps and sensitizer to adjust trap distribution and efficient up-conversion luminescence in rare-earth-doped luminescent materials. Besides, the as-prepared luminescent materials exhibit high thermal stability and excellent water resistance. On the basis of these properties, the samples were used to print luminescent images through a screen printing process on the film and banknote. The luminescent image in a film is showing different patterns and on a banknote is showing green emissions under different stimulations. These multimodal emissions demonstrate that the as-prepared sample is suitable for advanced information encryption and anti-counterfeiting.