| Popis: |
In this work, we investigated the features of the photoluminescence of C-Gd2(1-x)TbxEuxO3 luminophores at x=1.0 and 2.5 mol%, which are associated with the distribution of Tb3+ and Eu3+ activator ions over the centrosymmetric C3i and noncentrosymmetric C2 positions of cations in the bixbyite lattice, as well as in the positions at the boundaries crystallites CS. We studied the phase transformations of the samples, changes in the morphology of crystallites, photoluminescence spectra, and spectra of the far infrared region 50-600 cm-1 with changes in the annealing modes of the initial products of the sol-gel synthesis Gd2(1-x)TbxEux(OH)y(CO3)z· n(H2O) at temperatures of 900 and 1200oC in air and hydrogen. Correlations have been established between changes in the characteristics of the samples and the parameters of their annealing. Based on the analysis of these correlations, the redistribution of activators over the indicated cation positions was determined, and a model was proposed for identifying infrared absorption bands in accordance with the localization of activators along the cationic sublattices C3i and C2. Keywords: Gd oxide, luminescence activators Tb3+ and Eu3+, annealing in air and in hydrogen, correlation of photoluminescence and far infrared spectra, distribution of activators in the lattice. |
