A luminescent tris(2-thenoyltrifluoroacetonato) europium(III) complex covalently linked to a 1,10-phenanthroline-functionalised sol-gel glass

Lanthanide doped sol-gel glasses are an attractive type of luminescent material which can be processed at ambient temperatures. However, the solubility of the lanthanide complexes in the sol-gel matrix can be a problem and it is difficult to obtain a uniform distribution of the complexes ( avoidance of cluster formation). These problems can be solved by covalently linking the lanthanide complex to the glass matrix. In this study, a strongly luminescent europium beta-diketonate complex was immobilized on a 1,10-phenanthroline-functionalised silica sol-gel glass. The glass matrix was prepared by first reacting 5-amino-1,10-phenanthroline with 3-(triethoxysilyl) propyl isocyanate. The resulting compound, tetramethoxysilane ( TMOS) and diethoxydimethylsilane ( DEDMS) were hydrolysed and condensed at a neutral pH to a sol-gel glass. A tris(2-thenoyltrifluoroacetonato) europium(III) dihydrate complex was bound to the 1,10-phenanthroline groups on the silica gel and the coordinated water was expelled. High-resolution luminescence spectra were recorded and the radiative lifetimes were measured. It is shown that the spectroscopic behaviour of the luminescent materials is very comparable with that of the pure [Ln(tta)(3)(phen)] complex.