Dual-mode luminous and afterglow Ca3Al2Ge3O12:Yb3+, Er3+ phosphors for anti-counterfeiting and fingerprint verification

Abstract

Generally, traditional anti-counterfeiting fluorescent materials usually show a single peak under single wavelength excitation, which cannot meet the security of authentication information. Therefore, the simultaneous realization of multicolor, multiexcitation and multimodal luminescence properties remains a fascinating goal, especially in a single host. In this work, the sustained luminescent materials Ca3Al2Ge3O12:Yb3+, Er3+ (CAG:Yb3+, Er3+) were obtained, which can exhibit bright red and green luminescence with Er3+ ions under the 490 nm and near-infrared (980 nm) light excitation. The red emission dominates under the 980 nm laser irradiation, and the sample showed excellent photoluminescence (PL) and persistent luminescence (PersL) performance under the 490 nm irradiation, and the afterglow can exceed 6h. The up-conversion mechanism and emission properties of the phosphors were analytically studied, and some fluorescence-safe anti-counterfeiting patterns and multifunctional latent fingerprint (LFP) afterglow time imaging were designed as potential applications for anti-counterfeiting aspects and information storage.