Aluminum effect on photoluminescence properties of sol-gel-derived silicate glasses activated by rare-earth ions

SiO2:Al3+:RE3+ densified and transparent sol-gel samples have been prepared with different concentrations of aluminum and rare-earth (RE) ions. The RE ions are Eu3+, Sm3+, Er3 + or Er3 +/Yb3+. Each sample has been analyzed by means of site selective techniques: fluorescence line narrowing (FLN) and time resolved spectroscopy (TRS). In the light of the results, the commonly admitted cluster dispersion effect of aluminum can be read as a local crystal field modification for the RE ions.