Influence of xerogel matrices and co-ligands on luminescence parameters in materials with an europium(III) cryptate

A luminescent system based on the antenna effect consists of Eu(III) cryptate–co-ligand–xerogel matrix, where types of co-ligands and/or matrices changed. In the system a co-ligand and a matrix prepared by sol–gel method influence on luminescence properties of the materials with Eu(III) ions. Materials with the system mentioned above were characterized by such luminescence parameters as emission intensity, lifetime and quantum yield. Among the co-ligands used triphenylphosphide oxide (TPPO) exhibits the greatest improvement of emission intensity in the materials with different matrices. From the emission intensity point of view the material with Eu(III) cryptate complexed with TPPO and hosted in silica matrix presents the best result. Since there are no correlations between emission intensity and lifetime or quantum yield observed, different systems show improvement one of the parameters. Thus, the longest lifetime exhibits the Eu(III) cryptate without co-ligand entrapped in methyl-modified silicate, while the highest quantum yield presents the same complex in SiO2–Glymo. It is also observed that the higher organic content in a material, the more photochemically destabilized is the luminescent system excited by UV radiation.