An Excitation Wavelength-Dependent Color-Tunable La4ga2o9 : Bi3+, Er3+ Phosphor for Multicolor Anti-Counterfeiting

Stimulation-responsive luminescent materials have attracted intense attention due to their excellent optical properties in the anti-counterfeiting application. At present, most the anti-counterfeiting materials are based on single luminescence and fixed excitation patterns, resulting in a poor anti-counterfeiting effect. Therefore, developing multimodal anti-counterfeiting materials that change their luminous color under different wavelength stimuli has become a significant challenge. In this work, we reported a multimodal luminescent La4Ga2O9: Bi3+, Er3+ material, which could emit white, blue-green, baby blue and orange-yellow light at the excitation wavelength of 250nm~430nm. Moreover, it also showed green upconversion (UC) luminescence when irradiated with near-infrared (NIR, 980nm and 808nm) lasers. Notably, the material exhibited good humidity resistance and stability. Based on these integrated features, we designed an anticounterfeiting device. Results suggested that the anticounterfeiting device could quickly realize multimodal anti-counterfeiting using common light source (NIR (808nm or 980nm) laser and UV lamp). These combined characteristics will be difficulty to forge and show high security in anticounterfeiting applications