Multiple anti-counterfeiting realized in NaBaScSi2O7 with a single activator of Eu2+

Abstract

NaBaScSi₂O₇ doped with Eu²⁺ ions has been synthesized via a high-temperature solid-state reaction. The photoluminescence (PL) spectra of NaBaScSi₂O₇:Eu²⁺ phosphors demonstrate two emission bands centered at 421 and 500 nm due to the substitution of Ba²⁺ and Na⁺ ion sites with Eu²⁺ ions, respectively. Nd³⁺ and Pr³⁺ ions are introduced to re-construct the defect state of NaBaScSi₂O₇:Eu²⁺, which optimizes the long persistent luminescence (LPL) and photo-stimulated luminescence (PSL) properties of the as-obtained phosphor, respectively. The different release process of carriers trapped by defects contributes to a marked emission colour change of LPL and PSL from PL. The repeatability of write-in and read-out of carriers is confirmed by the LPL and PSL spectra after multiple cycles. The multi-functionalized dynamic fluorescence properties of the NaBaScSi₂O₇:Eu²⁺ phosphor as an optical storage material (OSM) provide a possibility for their application in concealed information encryption and dynamic anti-counterfeiting.