Dynamic photoluminescent and photochromic properties of CaAl₁₂O₁₉:Eu, Tb: A novel phosphor for advanced dual-modal multicolor anticounterfeiting

The integration of dynamic photoluminescence and photochromism to achieve dual-modal characteristics can substantially elevate the security of anticounterfeiting measures. In this study, a novel bifunctional phosphor, namely CaAl₁₂O₁₉:Eu, Tb possessing dynamic photoluminescence and photochromism, is developed by the sol-gel combustion method. As the duration of exposure to 254 nm ultraviolet radiation increases, the CaAl₁₂O₁₉:Eu, Tb phosphors exhibit exceptional dynamic luminescent characteristics and pronounced color changes. Furthermore, this exposure results in a photochromic phenomenon on the surface of the samples, causing a shift from white to light brown. With an increase in Tb doping concentration, distinct and diverse chromatic variations easily discernible are observed by the naked eye. In addition, the mechanisms underlying the dynamic photoluminescent and photochromic characteristics are analyzed herein. Furthermore, the application of the bifunctional phosphor CaAl₁₂O₁₉:Eu, Tb for advanced dual-modal multicolor anticounterfeiting is explored, offering enhanced security against duplication attempts.