Preparation and Luminescence Properties of Europium(III) and Tungstate Co-doped in Silicate Materials via The Sol-Gel Method

In the preparation of this precursor tetraethylortho silicate (TEOS),. sodium tungstate, ethyl alcohol and HCl were mixed and then heated at different temperatures for 3 h, leading to a luminescent compound. TG-DTA and IR show the stable and network structure of luminescence material. The dime-dimension fluorescence spectra excitation and emission spectra were used to characterize the luminescence properties of Eu(3+) doped silica materials. The results indicate that the luminescence materials were excited by (7)F(0)->(5)L(6) transition of Eu(3+) at 393 nn and the bands in the emission spectrum are corresponding to the (5)D(0)->(7)F(J) (J = 0, 1, 2) transitions of europium ion. The strongest band is the electronic dipole transition and the material in green lights. Furthermore, we found that WO(4)(2-) absorbed most of the energy and transferred to rare earth ion Eu(3+) effectively. The effect of WO(4)(2-) on the glass network and neighbouring configuration of Eu(3+) is discussed based on the optical spectra. The f-f transitions of the materials were interpreted by energy level of the luminescence materials. In this paper, we have also investigated the influence of tungstate content and annealing temperature in europium doped silicate materials on luminescence properties. Finally, the doped agent WO(4)(2-) sensitized the luminescence intensity of rare earth Eu(3+) more than 6 times when doped quantity is up to 3.26 %.