Chlorosulphate NaMgSO4 Cl phosphor doped with Ce(3+) and co-doped by Dy(3+) prepared by the wet chemical method was studied for its photoluminescence and thermoluminescence (TL) characteristics. The emission spectrum of Ce(3+) shows dominant peaks at 346 nm (excitation 270 nm) due to 5d → 4f transition. Efficient energy transfer occurs from Ce(3+) → Dy(3+) ions. Dy(3+) emission at 485 nm and 576 nm is due to (4) F9/2 → (6) H15/2 and (4) F9/2 → (6) H13/2 transitions of Dy(3+) ion respectively. The TL glow curves of NaMgSO4 Cl:Ce and Ce,Dy have been recorded for various concentrations at a heating rate of 2 °C/s irradiated by γ-rays at a dose rate of 0.995 kGy/h for 1 Gy, which peaks at about 241 °C and 247-312 °C respectively. Further, in changing the concentration level, the general structure of the intensity is found to increase. The main property of this phosphor is its sensitivity even for low concentrations of rare earth ions and low γ-ray dose. There is still scope for higher doses of γ-radiation. The phosphor presented may be used as a lamp phosphor as well as for TL studies.
An inorganic NaMgSO F fluoride material was prepared by the wet chemical method and studied for its photoluminescence (PL) and resonant-non-resonant energy transfer (RET and NORET) capabilities between Ce → Tb , Ce → Eu and Ce → Dy rare earth ions. The Tb emission for Ce → Tb transfers under ultraviolet (UV) wavelengths peaked at 491, 547, and 586 nm, for excitation at 308 nm due to D → F (J = 4, 5, 6) transitions. Eu emission spectra were observed at 440 nm (Eu ), 593 nm and 616 nm (Eu ) recorded for different concentrations of materials, whereas Dy emission from Ce → Dy transfer under UV wavelengths peaked at 485 nm and 577 nm due to F → H and H transitions. The purpose of the present study is to understand the RET and NORET effects of Tb , Eu and Dy co-doping in a NaMgSO F:Ce luminescent material, which could be used as a green-emitting material for lamp phosphors.
The thermoluminescence (TL) characteristics, effect of γ -radiation on NaMgSO 4 Cl: X (X = Tb; Ce, Tb; Dy; Dy, Eu) and trapping parameters in TL material prepared by wet chemical synthesis (WCS) method are studied. The intensity of these phosphors is compared with TLD CaSO 4 : Dy phosphor. The phosphor has a simple TL glow curve structure. The phosphors NaMgSO 4 Cl: Tb (between the range of 257-284°C); NaMgSO 4 Cl: Dy (173°C) and NaMgSO 4 Cl: Dy, Eu (156°C) have a single prominent peak, whereas NaMgSO 4 Cl: Ce, Tb has two peaks located at 154°C and 233°C indicating single and double trapping sites, respectively. It is found that intensity tends to be increase with increased concentrations of the activators. The TL glow curves of the phosphors have been recorded and irradiated at a rate of 0.99 kGyh −1 for 5 Gy γ -rays dose. The paper also discusses the kinetic parameters evaluated by Chen's half width method such as activation energy E (eV) and frequency factor S (s −1 ).
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