Effect of Dopants on Long Afterglow Properties of Y_2O_2S:Eu Phosphor and Its Long Afterglow Mechanism

Y_2O_2S:Eu phosphors doped with Mg~(2+), Ca~(2+), Sr~(2+), Ba~(2+), Ti~(4+) were studied by PL spectra, XRD, decay curve, relative brightness and TL spectra. The results show that those dopants do not change crystal structure of the host, but influence afterglow properties and relative brightness, and the decay curve comprised of a fast and a slow part is well exponential. Codopants of Mg and Ti suggest the longer afterglow duration than single ion doping, being dependent on their contents. The long afterglow mechanism of Y_2O_2S:Eu host materials was discussed on the basis of experimental results.