The Dy³⁺ doped silica glasses were prepared by sol-gel process with appropriate heat treatment. The structural changes during the gel to glass transition of the silica xerogels and the effect on fluorescence properties of Dy³⁺ were studied. For Dy³⁺ two dominant emissions occur at about 575nm(⁴F_9/2→⁶H_15/2) in the yellow region and 480nm (⁴F_9/2→⁶H_13/2) in the blue region. Both transitions are electric dipole in nature out of which (⁴F_9/2→⁶H_13/2) is hypersensitive. The intensity ratio (yellow to blue (Y/B)) of Dy³⁺ emission follows a trend parallel to the red to orange (R/O) ratio of Eu³⁺ in silica matrices. These ratios are influenced by the site symmetry and electro negativity of ligand atoms. The fluorescence intensity of Dy³⁺ ions increases remarkably when the doped xerogel is heat-treated. The fluorescence intensity ratio (Y/B) is used as a measure of the symmetry of Dy³⁺ environment during the gel - glass conversion, the higher the ratio, the more asymmetric is the environment. The high value of the intensity ratio of the 1000°C heated gel showed that the Dy³⁺ was embedded in the glassy silica network with an asymmetric environment. The FTIR and thermo gravimetric analysis (TGA) clearly showed the complete densification (density=2.2 gm/cm³) of the gels around 1000°C.

Date Published: 29 August 2002
PDF: 7 pages
Proc. SPIE 4905, Materials and Devices for Optical and Wireless Communications, (29 August 2002); doi: 10.1117/12.481057

Published in SPIE Proceedings Vol. 4905:
Materials and Devices for Optical and Wireless Communications
Constance J. Chang-Hasnain; YuXing Xia; Kenichi Iga, Editor(s)