Deep trap engineering in Gd3GaO6:Bi3+ persistent phosphors through co-doping lanthanide ions

The development of luminescent materials for optical information encryption has received great attention in recent years. However, single-mode luminescent materials greatly limit their information capacity and encryption level. Here, a broad range of gadolinium gallate-based oxide persistent material systems with tuneable persistent luminescence (PersL) are rationally designed by the construction of electron–hole defect pair structures between Bi3+ and a set of lanthanide ions (Ln3+) (Ln = Eu, Sm, Tb, Dy, Pr and Ce). These phosphors exhibited excellent quadruple-mode luminescence including photoluminescence (PL), PersL, thermoluminescence (TL) and photo-stimulated luminescence (PSL). In particular, a quadruple-mode ‘morning glory’ encrypted pattern using these multimode persistent phosphors as storage media demonstrates multilevel optical information storage accompanied with dynamical encryption. These findings described here provide a universal methodology to construct a novel class of persistent materials with tuneable PersL emission and high information storage capacity.