Enhancement of luminescence intensity and increase of emission lifetime in Eu3+-doped 3CdO–Al2O3–3SiO2 amorphous system

Intense photoluminescence at room temperature was observed in amorphous cadmium aluminum silicate doped with europium prepared by the sol–gel method. The structure of the 3CdO–Al2O3–3SiO2:Eu3+ system (CAS:Eu3+) has been determined by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The excitation and the emission spectra indicated that the red characteristic emission (611 nm) of CAS:Eu3+ under UV excitation due to 5D0→7F2 electric dipole transition is the strongest. Both XRD data and the emission ratio of (5D0→7F2)/(5D0→7F1) reveal that the Eu3+ is in a site without inversion symmetry. The maximum photoluminescence intensity has been obtained for 25 mol% concentration of Eu3+ in CAS, and the intensity enhancement and lifetime increase of Eu3+ with increasing sintering temperature were observed due to the less OH-content in the samples.