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.