Bluish-green high-brightness long persistent luminescence materials Ba4(Si3O8)2：Eu2+Pr3+, and the afterglow mechanism

Abstract

A bluish-green long persistent luminescence material Ba4(Si3O8)2:Eu2+, Pr3+, was synthesized by traditional solid state method in a reductive atmosphere According to the photoluminescence and afterglow spectra measurement, the emission center is the cation Eu2+ in the photoluminescence and afterglow procedure. The Pr3+ co-doped sample forms new defects which could capture current carriers after excitation. On the basis of thermoluminescence and afterglow decay measurement, the afterglow intensity of Pr3+ co-doped sample sharply enhances as compared with Eu2+ doped one, the reason is that the lower depth traps are generated in the shallow trap areas (T1 region). At the same time, the Pr3+ co-doped sample have longer afterglow decay than that doped with only Eu2+; the reason is that the deep traps concentration decreases in the deep trap areas (T2 region). The afterglow mechanism of Pr3+ co-doped sample have two different excitation paths, path 1: the electron of the host is directly projected to traops at 268 nm excitation; path 2 the electron of the Eu2+ corresponds to the transitions from the ground state to the 5d excited state at 330 nm excitation. Then the different afterglow mechanism of phosphor was produced.