 1996 study by Matsuzawa et al. reported extremely long-lasting afterglow of senior al-204-EU2 plus codiped with di-3 plus ions, which was more than 10 times brighter than ZNS-CU company. Since then, research for stable and efficient persistent phosphorus has gained popularity but the number of such materials is still relatively low and the mechanism behind this phenomenon is unclear. This review provides an overview of important classes of known persistent luminescent materials based on EU2 plus emission and their preparation, as well as a closer look at suggested models and mechanisms for bright afterglow in various compounds. This article was authored by Cohn Van Den Eakout, Philippe F. Smit and Dirk Pillman.