Spectroscopic study of Eu3+-doped and Eu3+,Y3+-codoped SiO2 sol-gel glasses

Eu3+-doped and Eu3+,Y3+-codoped SiO2 glasses were prepared through sol-gel technology. Effects of annealing on the spectroscopic properties. including photoluminescence, decay processes and spectral hole burning, were investigated. It was found that clusterization of Eu and Eu-Y may take place during the annealing process, and the environment of Eu ions was changed from a site of near inversion symmetry to one with more non-inversion character, resulting in an increase of the D-5(0)-->F-5(2) transitions relative to that of the transitions to F-5(0), and F-5(1). The affects of clusterization on the spectroscopic properties are discussed. (C) 2000 Elsevier Science S.A. All rights reserved.