Time-dependent dynamic multicolor afterglow of simple LiGa5O8:Eu3+/Tb3+ particles for advanced anticounterfeiting and encryption

Abstract

Long-persistent luminescence (PersL) materials have shown great promise on account of their diverse utilization in anticounterfeiting and encryption. Nevertheless, time-dependent dynamic multicolor afterglow is rarely reported, especially for single-component oxide-based materials. In this work, a series of LiGa₅O₈:Eu³⁺/Tb³⁺ phosphors exhibit time-dependent dynamic multicolor afterglow from blue to red or green over several seconds after ceasing the excitation. Both experimental and computational data confirm that the color evolution results from different energy transfer processes between traps and luminescent centers. The processes are probably controlled by thermally activated exciton diffusion and the electron tunneling effect. This dynamic multicolor afterglow of LiGa₅O₈ phosphors allows their applications in anticounterfeiting and encryption with high security levels.