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

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 350 nm UV light, the emission line at 576 nm(⁴F_9/2–⁶H_13/2) and 487 nm (⁴F_9/2–⁶H_15/2)from the Dy³⁺ions coexist with the wide emission band from the K₂Mg(SO₄)₂host. The excitation spectra of the emission at 576 nm consist mainly of the strong excitation band of the K₂Mg(SO₄)₂host at 350 nm.TL characteristics show excellent results by the same SSD method. The samples were irradiated by γ-radiation for 5–30 Gy from ⁶⁰Co source at the dose rate of 0.322 kGy h⁻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 ChenГ—Віs method. The values of trap depth (E) and frequency factor (s) were found to be 0.77±0.002 eV and 3.5×10⁸ s⁻¹ respectively. The study of PL, TL and evaluation of trapping parameters has been done and discussed for first time.