Influence of Li+ and Dy3+ on structural and thermoluminescence studies of sodium sulfate

Abstract

Na 2 SO 4 , Na 2 SO 4 : Dy 3? , LiNaSO 4 and LiNaSO 4 : Dy 3? nanoparticles successfully synthesized by slow evaporation technique followed by calcination at 400 o C. The resultant products were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared and UVVis spectroscopy. The average crystallite size was calculated using Debye-Scherrer's formula and WilliamsonHall's (W-H) plots. The optical energy band gap (E g ) was estimated from Wood and Tauc's relation, which varies from 3.70 to 4.45 eV. The variation in band gap values attributed to large degree of structural defects. Thermoluminescence studies were investigated using c-irradiation in the dose range 0.5-5 kGy at a heating rate of 5 K s -1 . The samples Na 2 SO 4 and LiNaSO 4 showed a well-resolved glow peak at *180 and *170°C, respectively. The prominent glow peak at *175°C along with shouldered peak at *60°C was observed for Na 2 SO 4 : Dy 3? . LiNaSO 4 : Dy 3? showed prominent glow peak at *100°C and a small shoulder peak at *180°C. The addition of isovalent (Li ? ) quenches the TL intensity, whereas the hypervalent (Dy 3? ) increases the intensity of Na 2 SO 4 . The variations of TL intensity for all the phosphors follow linear behavior up to 5 kGy and were useful in radiation dosimetry. The kinetic parameters (E, b and s) were estimated from the glow peak shape method.

Growth and Various Characterizations of Lithium Sulfate Monohydrate Single Crystals after Eu3+ and Tb3+ Ion Doping

“…The luminescence of europium in the trivalent state in some lithium and sodium sulfates was also undertaken and in these crystals, they usually work as activators. [22,23] But such sulfates are not grown in the form of crystals and the energy transfer mechanism in such RE-doped crystals was not discussed.…”