Investigation of Er, Er:Yb and Er:Tm systems in silica sol-gels

Luminescence spectra and lifetime of Eu(III) and Tb(III) ions in complexes with glycine (AAA), glycolic acid (GA), aspartic acid (ASP) and malic acid (MA) were studied. The effect of the amino-NH2 and hydroxyl-OH groups on the intensity and lifetime of the lanthanides luminescence were examined. Hydration number for Eu(III) in the systems studied indicated the involvement of carboxyl and hydroxyl groups as well as donor nitrogen atoms in the coordination. The phenomenon of Gd(III) ion emission quenching was analyzed and quantitatively described by determination of the quenching constant KSV.