PHASE DEPENDENCE OF LUMINESCENT EMISSION OF Eu²⁺ DOPED SrAl₂O₄

In this work, we made five samples of SrAl₂O₄: Eu²⁺, Dy³⁺, the \alpha phase and \beta phase SrAl₂O₄:Eu²⁺,Dy³⁺ powder and pellet samples, and \alpha phase single crystal. We have measured the emission spectra of all the samples. All the emission peaks are around 520 nm, which correspond to the transition from 4f⁶5d¹(²E_g) to 4f⁷(⁸S_7/2) of Eu²⁺ in SrAl₂O₄ host. The intensity of emission of the \beta phase is stronger than that of the \alpha phase. We believe that it is because the Eu²⁺ ions have occupied the two types of sites in the \alpha phase SrAl₂O₄ host and the lifetime of the transition of Eu²⁺ in the A site is longer than that in the B site. This result also proves that the \beta phase of the material is brighter than the \alpha phase. In addition, the \beta phase can be achieved by quenching technique.