Photoluminescence and thermoluminescence properties of Dy3+/Eu2+ activated Na21Mg(SO4)10Cl3 phosphors

In the present work luminescence properties of rare earth (RE) doped Na21Mg(SO4)10Cl3 were studied. Modified solid state method was employed to synthesize the phosphors. The influence of RE (RE=Dy and Eu) doping on the luminescence properties of as prepared phosphor were investigated in detail. PL emission spectra of the Na21Mg(SO4)10Cl3:Dy phosphor exhibits the characteristic emission of Dy. The characteristic Dy3+ emission in the form of peaks around 482 and 576 nm corresponding to transitions 4F9/2→6H15/2 and 4F9/2→6H13/2 was seen when excited by excitation wavelength 351 nm. However, interesting thermoluminescence results are observed in case of Dy as well as Eu doped Na21Mg(SO4)10Cl3. The TL glow curves for Na21Mg(SO4)10Cl3:Dy exhibit broad peak composed of three overlapping peaks, these peaks were deconvoluted using deconvolution program. The peaks at different temperatures indicate that different sets of traps are being activated within the particular temperature range each with its own value of activation energy (E) and frequency factor (s). The peaks observed were due to formation of trap levels by γ-rays irradiation and subsequently activation of traps on thermal stimulation. The trapping parameters for both the samples were calculated using Chen's peak shape method and reported in this paper.