Lattice‐Distortion Enhanced Narrow‐Band Green Emission Phosphor for Advanced Information Encryption and X‐Ray Imaging

Long persistent luminescence (LPL) materials hold enormous potential for optical information encryption and storage. Nevertheless, the precise and facile modulation of the luminescence performance remains a great challenge of LPL materials, which severely limit their practical application. Herein, the accurate regulation of the luminescence and afterglow characteristics of Na 2 ZnGeO 4 (NZGO):Mn 2+ phosphor is achieved via a facile lattice distortion engineering strategy. Structural and spectroscopic investigations verify that modulating the sintering temperature produce lattice distortion of NZGO, which simultaneously boosts LPL intensity/duration and the X‐ray excited optical luminescence intensity. Remarkably, the quantum efficiency rises drastically from 1.2% to 48.6%, corresponding to a 40.5‐fold enhancement. Theoretical calculations reveal that elevated sintering temperature induces aggravated lattice distortion and abundant oxygen vacancy defects, being favorable for LPL formation. Quantitatively, the oxygen defect concentration increased by 4.84 times, accompanied by over 7‐fold prolongation of the LPL decay time. By virtue of the modulated luminescence and afterglow behaviors, the obtained NZGO:Mn 2+ phosphors exhibit promising prospects for advanced optical information anti‐counterfeiting and X‐ray imaging.