LiGa5O8: Fe3+: A novel and super long near-infrared persistent material

The development of near-infrared persistent materials has become a popular research area owing to their diverse applications. However, the efficient emitters for these materials remains limited. Cr3+ is one of the strongest candidates, since it displays better performance with long duration. Fe3+ is a potential nontoxic alternative although its performance is not as good as Cr3+. In this study, a series of novel Fe3+-activated near-infrared long afterglow phosphors of LiGa5O8 have been prepared. Photoluminescence and persistence luminescence spectroscopy have been collected to investigate its optical properties. Furthermore, the trap characteristics of the samples were systematically analyzed by collecting thermoluminescence signals. The results indicate that there is an intense near-infrared emission centered at 675 nm and a long afterglow duration of more than 28 h for the optimized sample. Trap analysis indicates that oxygen vacancy defects are not the primary reasons for the extraordinarily long afterglow in these samples. Instead, the interaction of other trap types, such as antisite defects, probably contribute to the excellent afterglow properties of the material.