Preparation and optical characterization of organoeuropium-doped silica gels

Gels have been investigated as potential matrices for rare earth luminescen ce. The use of complexing ligands in the sol-gel synthesis of the rare-eart h doped glasses has been suggested to improve the rare earth ion luminescen ce properties in these matrices due to the changes in the local environment experienced by the rare earth ion. In this work, transparent Eu3+-doped ge ls were prepared from Si(OCH3)(4) and fluorinated and/or complex-forming Eu 3+ precursors (Eu(fod)(3), (CF3SO3)(3)Eu, (CF3 CO2)Eu . 3H(2)O, Eu(thd)(3) and Eu(acac)(3)). Results of emission, fluorescence line narrowing and life times studies of Eu3+-doped gels derived from Si(OCH3)(4) and fluorinated/c helate Eu3+ precursors are presented. The results were interpreted in terms of the evolution of the Eu3+ fluorescence in systems varying from solution s to the gels densified to 800 degrees C. Analysis of the fluorescence deca ys of the D-5(0) State suggests that the use of the fluorinated Eu3+ precur sors reduces the hydrophobic content in the silica gels matrices. FLN studi es indicate that Eu3+ clustering occurred in all densified samples.