Energy transfer between Eu 3+ ions in sol–gel derived silica glasses

Abstract

Time-resolved fluorescence line narrowing technique has been used to analyse the evolution of the 5D 0→ 7F 0 emission of Eu 3+ ions in sol–gel derived silica glasses. These samples were doped with 2.5 mol% of Eu 3+ and heat treated at different temperatures. Background fluorescence, coming from Eu 3+ ions excited by energy transfer processes, was observed in these experiments. Using a previously proposed equation model, a study of the multipole character of the interaction between Eu 3+ ions was performed. The annealing process carried out in the samples causes important changes in the efficiency of energy transfer process and in its multipole character, varying from S=6 (in a sample treated at 400°C) to S=10 (in a sample treated at 600°C), indicating that the environment of Eu 3+ ions has been modified.