Germanium substitution endowing Cr3+-doped zinc aluminate phosphors with bright and super-long near-infrared persistent luminescence

Novel Cr3+-doped Zn1+xAl2-2xGexO4 near-infrared persistent phosphors exhibit persistent luminescence lasting for more than 120 h. Through studying the presence of antisite defects, distribution of trap states, luminescence behaviors and first principle calculations, the super-long-persistent luminescence is found to mainly from the GeZn○○ and GeAl○ in the spinel structure that inducing shallow and deep defect states to serve as efficient traps.284