Dual-wavelength excited luminescence properties of NaYbF4:Er3+ for flexible anti-counterfeiting

Multiple encryption of information is the key to the upgrade of anti-counterfeiting technology. However, developing reliable multimode anti-counterfeiting materials is still a challenging work. Herein, a series of Er-doped NaYbF4 microprisms was synthesized. The as-prepared microprisms could show variable emission from red to yellow under the irradiation of 980 nm, and exhibit red at 365 nm UV light, respectively. Near-infrared excitation is achieved through the upconversion process of Er–Yb pairs, while UV excitation is achieved through Er ions. Its crystal structure, morphology, and photoluminescence features were analyzed. To broaden its practical application, the powders were combined with TPU to form a film with excellent stretchability, transparency, and water resistance. Our work demonstrates a dual-wavelength excited luminescence material, providing a practical reference for the application of anti-counterfeiting materials.