Luminescence of cryptate-type Eu³⁺ complexes incorporated in inorganic and ormocer sol-gel matrices

Two new complexes of Eu-bipyridine (Eu-AA and Eu-BB) were incorporated into sol-gel derived thin films based on zirconia oxide and organically modified sol-gel hybrid zirconia-silica-urethane ormocer (ZSUR). The absorption and the emission intensities of the composites were compared to the intensity of the Eu oxide doped films and to the other complexes studied recently. The site symmetry of the Eu complexes and Eu oxide in used matrices were studied as well. The intensification of fluorescence, as compared to europium oxide, value was increased by a factor of 64 in amido-amino complex (Eu-AA), and of 2044 in fluorine complex (Eu-BB) as a result of efficient charge transfer from the combined ligand-europium state to europium high ligand levels. The lifetimes from the ⁵D₀ state of the complexes are measured and the results explained.