Effects of annealing on luminescence of CaWO4:Eu3+ nanoparticles and its thermoluminescence study

Eu3+ doped CaWO4 nano-sized phosphor powders with tunable optical properties were successfully prepared at comparatively low temperature (130 °C) in ethylene glycol (EG) medium and were further annealed to study heating effects in their luminescence properties. The particles exhibit the tetragonal scheelite structure. The luminescence study of the annealed nanoparticles leads to the confirmation that CaWO4:Eu3+ shows a strong red emission at 614 nm originating from 5D0 → 7F2 transition. The optimum concentration of Eu3+ for the highest luminescence is found to be 20 at.% and the luminescence intensities of the prepared nanoparticles increase with increasing annealing temperature from 500 to 900 °C. Thermoluminescence (TL) intensity of CaWO4:Eu3+with two prominent peaks at 393 and 514 K is found to be dependent on Eu3+concentration with highest TL intensity at 3 at.% of Eu3+.

The emission spectra of CaWO4:Eu3+ (very low concentration of Eu3+ ion) excited at 243 nm.Figure optionsDownload as PowerPoint slideHighlights
► Highly luminescent CaWO4 : Eu3+ nanopartilces have been synthesized in ethylene glycol route and further annealed.
► The luminescence intensity increased manifolds due to annealing at higher temperatures.
► Thermoluminescence (TL) studies of CaWO4:Eu3+ (x at.%) samples show that the TL intensity depends upon the concentration of Eu3+.
► 3 at.% Eu3+ have the highest TL intensity.