Synthesis and luminescence of SrAl2O4: Eu2+, Dy3+

Abstract

This study systematically discusses the effects of the synthesis process of SrAl2O4:Eu2+, Dy3+ in reducing the firing temperature and reducing the percentage of concentration of Eu2O3 and Dy2O3. The influence of firing temperature and rare earth doping on crystal structure, morphology, and its luminescent properties were analyzed by X-ray diffraction (XRD), Raman scattering, Photoluminescence excitation (PLE) and photoluminescence emission (PL) spectroscopy, and scanning electron microscopy (SEM). The emission intensity becomes stronger as the firing temperature increases from 1100°C to 1250°C. SrAl2O4:Eu2+, Dy3+ firing at 1250°C shows the maximum photoluminescence intensity at 0.5 mol % Eu2O3 and 1 mol % Dy2O3 addition. A phase transformation from SrAl4O7 to SrAl2O4 and Sr4Al14O25 is found with increasing firing temperature. The synthesized phosphors reveal the presence of the crystalline monoclinic structure of SrAl2O4 as a major phase (JCPDS card no. 74-0794) and the intermediate phase orthorhombic structure of Sr4Al14O25. Small amount of doped Eu2O3 and Dy2O3 has almost no effect on the crystalline phase composition. The proposed firing temperature and mole concentration of the activator and co-activator is lower in comparison with other conventional solid state methods and allows us to obtain the SrAl2O4:Eu2+, Dy3+ phosphor with improved properties.