Effects of surrounding ion on Eu3+ luminescence in glass

The energy relaxation of excited Eu3+ in glass hosts is investigated in thi s study. Eu3+ ions are incorporated in both melted glass and sol-gel derive d glass. The strong Eu3+ emission lines from D-5(0) to F-7 level show that the glass hosts provide the effect of the random structure of the silica ne twork on the Eu3+ ion. The relative intensities of the Eu3+ emission depend strongly on the host glass types and excitation wavelengths. The D-5(0) em issions of Eu3+ in the sol-gel derived glass are more efficient than in the melted glass due to an excitation to the charge-transfer-state at 250 nm. The promotion of the charge-transfer-state excitation in the sol-gel derive d glass, which is annealed at 400 degreesC, comes from the anions encapsula ted during the sample preparation step. The energy relaxation processes are identified from the wavelengths of the excitation peaks of Eu3+. The roles of UV-absorbing cations. Ce3+ and Ti4+, which are codoped in the glasses, are examined. (C) 2001 Elsevier Science B.V. All rights reserved.