Thermoluminescence studies and detailed kinetic analysis of Sr4Al14O25:Eu2+, Dy3+ phosphor

The Sr4Al14O25:Eu2+ and Sr4Al14O25:Eu2+, Dy3+ phosphors were prepared by the conventional solid state method. The structural characterization, surface morphology and the thermoluminescence properties of these phosphors were studied and then the obtained results were compared. The crystal structure of the Sr4Al14O25:Eu2+, Dy3+ phosphor was determined as orthorhombic crystal system with Pmmm space group with unit cell parameters of a=24.7746 Å, b=8.4949 Å, and c=4.8819 Å; α=β=γ=90°; and V=1027.438 (Å)3. Both Eu2+ and Eu2+/Dy3+ co-doped phosphors have similar XRD pattern because of a little amount of doping ions. The thermoluminecence properties of these phosphors were investigated and the results were also compared. The results have proved that the total peak intensity for Eu2+ and Dy3+ co-doped phosphor is higher than that of Eu2+ doped. The trap parameters which are mainly activation energy (Ea), the frequency factor (s) and the order of the kinetics (b) were evaluated by using the computerized glow curve deconvolution (CGCD) method. The calculated trap depths are in the range from 0.55 to 1.27 eV.