Fluorescence Studies of Dy3+ Ions in Silica Sol Gel

摘要

The fluorescence properties of Dy~(3+) ion are utilized to study the structural changes during the gel to glass transition of the silica xerogels. The fluorescence intensity ratio (yellow to blue, Y/B) is used as a measure of the symmetry of rare earth ion environment during the gel-glass conversion. The high value of the intensity ratio of gel heated to 1000 ℃ showed that the rare earth ions are embedded in the glassy silica network with an asymmetric environment. Fluorescence study is also used to characterize the effect of metal cation co-dopants on the state of aggregation of rare earth ions in silica sol gel. The addition of co-dopants inhibits the clustering of rare earth ions and promotes better dispersion. The inhibition of clustering is correlated with the generation of strong crystal field bonding sites for rare earth ions in the presence of co-dopants.