Preparation and luminescence properties of SiO2-ZrO2 and SiO2-Ta2O5 composite materials doped with a terbium(III) complex

The terbium(III) 2,2'-bipyridyl complex, [Tb(bpy)(2)]Cl-3, was incorporated for the first time into partially metal oxide-substituted silica matrices derived from tetraethyl orthosilicate (TEOS) and metal alkoxides (M(OR)(n), M= Zr and Ta) via sol-gel process. The optical properties of the obtained [Tb (hpy)(2)]Cl-3-dispersed inorganic-organic composite materials were char acterized by measurements of photoluminescence, transmittance, infrared spe ctra and X-ray diffraction patterns. The emission intensity of the (SiO2-Mx Oy):Tb (bpy)(2)(3+) composite phosphors was dependent on the kind and conte nt of metal oxide component in the matrices and maximized at the matrix com position of Si :M=9 : 1 in molar ratio in either case. In particular, for t he SiO2-Ta2O5 matrix system with the composition of Si : Ta=9 : 1, the comp lex was incorporated into the host media at concentrations up to 20 mol%, w hich resulted in composite phosphors with a good transparency. Under the op timized preparation conditions, the emission intensity of such organically modified ceramic (ORMOCER) (SiO2-Ta2O5): Tb(bpy)(2)(3+) phosphors maximized at ca. 75% vs. LaPO4: Ce,Tb (a commercially available lamp phosphor as the standard substance) with complex concentrations of 10-15 mol%.