Developing dual-mode material with ultraviolet and visible persistent luminescence for multi-mode anti-counterfeiting and information encryption

Abstract

Recently, persistent luminescence materials (PLMs) have attracted extensive attention in the anti-counterfeiting and information encryption fields. Unfortunately, single visible persistent luminescence (PersL) demonstrates limited information security because the changes in information coded by visible PersL can be observed by the human eyes. In this work, we develop a dual-mode PLM with ultraviolet (UV) and visible PersL, Mg₃Lu₂Ge₃O₁₂:Bi³⁺,Re³⁺ (Re³⁺ = Pr³⁺ and Tb³⁺) (MLGO:Bi³⁺,Re³⁺). The emitter Bi³⁺ yields invisible UV PersL, and the emitter Re³⁺ exhibits visible PersL. The color of visible PersL can be changed upon variation of the Re³⁺ content. Because the UV PersL hidden behind visible PersL is invisible to the human eyes, the capacity of invisible information encryption can be realized. With a specific filter and a charge coupled device camera for detection, the encrypted optical information will appear. Based on the dual-mode PLM with UV and visible PersL, we design the four-mode information encryption method and display excellent information encryption capability.