Tuning Cu2+-doped NaGaO2 for enhanced photoluminescence via Al3+ ion-preferential substitution

To overcome the limitations of static fluorescent anti-counterfeiting, this study proposes a dynamic encryption method based on the afterglow of materials. Through defect engineering, Cu 2+ single-doped and Cu 2+ /Al 3+ co-doped NaGaO 2 (NGO) phosphors were synthesized. The doping of Al 3+ enhances the yellow emission at 610 nm through lattice distortion and defect optimization, while effectively modulating the decay kinetics of Cu 2+ . Millisecond-level lifetime differences were achieved under same-color emission, enabling temporal information encryption. This approach breaks the conventional reliance on multi-color systems and realizes dual-dimensional encoding in both color and time, offering a high-capacity, counterfeit-resistant anti-counterfeiting strategy.