Defect Chemistry of Long Afterglow Material SrAl2O4: Eu, Dy

The hydrolysates of activated Al-Sr alloy powder were used as a precursor. The long afterglow material SrAl2O4: Eu, Dy was prepared by high temperature solid reaction. Influences of concetration of Dy (x=0, 0.01, 0.02, 0.03mol%) on the phosporescent properties and characters of afterglow were studied. The results show the initial luminescent intensity and the duration time of SrAl2O4: Eu, Dy is inscreased with the concentration of Dy inscressing. The defect chemistry of long afterglow material SrAl2O4: Eu, Dy was analyzed. The doped rare erath ions occupy the lattice situation of Sr2+ in SrAl2O4 crystal structure. And then the impurity defect such as Eu-Sr(x), Eu-Sr* and Dy-Sr* is formed. The initial luminescent intensity is decided by the concentration of Eu-Sr(x), as emission centers. In order to keep neutral balance, the intrinsic defect V-Sr(II), changed negative is attracted around the Eu-Sr*. and Dy-Sr*, the impurity defect charged positive and formed the traps can trap the hole changed positive. The duration time is controled by the concertration and energy level of V-Sr(II).