MgGa2O4:Sm3+ with photochromism, dynamic photoluminescence and persistent luminescence for advanced anticounterfeiting

Materials integrating photochromism (PC), dynamic photoluminescence (PL) and persistent luminescence (PersL) exhibit significant potential for advanced anticounterfeiting and high-security information encryption through their multi-modal optical responses to external stimuli. Nevertheless, achieving the synergistic integration of these optical phenomena within a single material remains a significant challenge due to complex defect-related energy transfer processes. In this work, we developed a series of MgGa 2 O 4 :Sm 3+ (MGO:Sm) phosphors exhibiting reversible white-to-gray PC under 254 nm UV irradiation, accompanied by time-dependent dynamic PL color variations from dark red to light pink (or blue). Furthermore, the phosphors exhibit dynamic PersL, with emission color shifting from light pink (or blue) to red over time. Remarkably, Sm³ + doping not only enhances PC response but also enables color-tunable dynamic PL and PersL. Further analysis reveals that these multi-modal optical properties originate from complex interactions between traps, defect levels, and Sm³ + ions. The superior performance of MGO:Sm phosphors demonstrates their promising utility in advanced anticounterfeiting and encryption technologies.