Preparation of long-afterglow Sr4Al14O25-based luminescent material and its optical properties

Sr4Al14O25-Eu,Dy photoluminescent material with high brightness and long afterglow was prepared by sintering at high-temperature and weak-reducing atmosphere. The luminescent properties were studied systematically. The analytical results indicate that the emission spectra of Sr4Al14O25-Eu,Dy are similar to that of Sr4Al14O25-Eu. Both of them have two main peaks near 424 and 486 nm, respectively, which are ascribed to two types of Eu2+ that exist in the Sr4Al14O25 matrix crystal. However, the Sr4Al14O25-Eu phosphor does not have the long-afterglow phenomenon shown by Sr4Al14O25-Eu,Dy. As for the mechanism of the long afterglow, Dy3+ acts as the trap level and captures the free holes in the system. It is the trapped-detrapped recombination process that results in the long-afterglow phenomenon of this phosphor. 10 refs.