Photo and thermoluminescence in K2Mg(SO4)2: Dy phosphor and evaluation of trapping parameters

Abstract

The prepared phosphor K2Mg(SO4)2:Dy is synthesized by solid state diffusion (SSD) method. The sample was studied for its photoluminescence (PL) and thermoluminescence (TL) characteristics. In the emission spectra of K2Mg(SO4)2:Dy excited by 350nm UV light, the emission line at 576nm(4F9/2–6H13/2) and 487nm (4F9/2–6H15/2)from the Dy3+ions coexist with the wide emission band from the K2Mg(SO4)2host. The excitation spectra of the emission at 576nm consist mainly of the strong excitation band of the K2Mg(SO4)2host at 350nm.TL characteristics show excellent results by the same SSD method. The samples were irradiated by γ-radiation for 5–30Gy from 60Co source at the dose rate of 0.322kGyh−1. The TL glow curve shows the simple structure having the peak temperature nearly at 185°C. The single peak is due to the possibility of formation of only one kind of trapping site due to γ-irradiation. The effect of concentrations of Dy and γ-radiation doses does not change the general structure of the TL glow curve but the intensity is found to be increased as per the higher concentrations and dose. The trapping parameters are also evaluated by Chen׳s method. The values of trap depth (E) and frequency factor (s) were found to be 0.77±0.002eV and 3.5×108s−1 respectively. The study of PL, TL and evaluation of trapping parameters has been done and discussed for first time.