Multicolor real-time and differentiation displays in NaNbO3-based photochromics for advanced anti-counterfeiting applications

Advanced multifunctional photochromic materials have important significance in the fields of anti-counterfeiting and optical information storage. Herein, we report novel Li doped NaNbO3:Er3+/Eu3+ multifunctional materials. Tunable multicolor emission, photochromism, and reversible multimode luminescence modulation are integrated in a single matrix through Li doping and defect engineering strategies. Real-time visualized emission colors dynamically change from green, yellow, orange to red by controlling the excitation wavelengths or photochromic processes. Notably, Li doping synergistically boosts the photochromic efficiency (46.2 % from 15.6 %) and luminescent modulation ratio (93.7 % from 10.1 %). The multimodal luminescence can be reversibly modulated by alternating ultraviolet light (379-397 nm), near infrared light (980 nm), or thermal stimulation. Based on multicolor emission and luminescent modulation behaviors, the designed patterns can realize real-time and differentiation displays in the dark or bright fields, significantly improving the anticounterfeiting level and storage ability. These findings offer new insights into the development of multifunctional integrated materials for advanced anti-counterfeiting and optical storage applications.