XANES and XEOL studies of Eu-doped calcium tungstate in silica synthesized by sol-gel method

Europium-doped calcium tungstate (CaWO₄:Eu) was synthesized by a modified Pechini method. X-ray absorption near-edge structure (XANES) and X-ray excited optical luminescence (XEOL) was employed to probe the chemical and luminescence properties of CaWO₄:Eu. XANES results demonstrate that the chemical environment around calcium in the doped CaWO₄ is similar to that of undoped CaWO₄. On the other hand, chemical environment around oxygen is very different. Moreover, the results suggest that contributions to luminescence in the sample are from both silica (from silica matrix) and CaWO₄. Using XEOL, luminescence pathways and efficiency associated with the system can be identified.