| Abstract
| - Luminescent materials prepared by the sol−gel method are composed of Eu(III) complexes entrapped in a xerogel matrix. Luminescence action in the materials based on the antenna effect is effectively quenched by O−H oscillators surrounding the central ion. To improve luminescence lifetime and quantum yield, the coordination environment of Eu(III) and matrix were modified. A cryptand ligand with aromatic groups and an aromatic coligand around Eu(III) initiate the antenna effect and remove the quenchers.
- This study focuses on luminescent materials based on the antenna effect and prepared bythe sol−gel method. These materials are composed of a Eu(III) complex (luminescence center)entrapped in a xerogel matrix. Luminescence properties of the lanthanide-based emittingmaterials depend on the efficiency of energy transfer from the absorption center (ligand) tothe emission center (central ion) and on the concentration of quenchers (O−H oscillators)surrounding the central ion. In this study, such luminescence properties as * lifetime andquantum yield were improved by modifying the coordination environment of the central ionand changing anion groups and matrixes. The results of the experiments on the compositionof the coordination sphere show that a cryptand ligand with aromatic groups and an aromaticcoligand efficiently initiate the antenna effect, thus isolating the central ion from everyefficient quencher, e.g., water molecules. Luminescence properties also depend on the anionin the Eu(III) complex salt, the type of matrix material, and the concentration of water andOH groups in the matrix. These luminescent materials have been tested for theirphotochemical stability under continuous UV irradiation.
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