Structural, optical and thermal studies of Eu3+ ions in lithium fluoroborate glasses

Borate glasses doped with trivalent europium were prepared by the conventional melt quenching technique, in the chemical composition of (49.99-x)B2O3 + 25Li2O + 25LiF+xEu2O3 by varying the concentration of the rare earth ion in the order 0.01, 0.1, 1, 2 and 3 wt% and their structural, luminescence and thermal behavior have been reported. The XRD and FTIR spectra reveal the glass structure and the functional groups. The UV–VIS, luminescence spectra and lifetime of the Eu3+ ions were measured. The local site symmetry around the Eu3+ ions were evaluated through the luminescence intensity ratio (R) of the 5D0 → 7F2 to 5D0 → 7F1 transitions. Optical measurements have been carried out to explore the optical properties such as bonding parameters, Judd–Ofelt parameters, stimulated emission cross-section, transition probability, branching ratio, radiative lifetime, etc. The lifetime measurements of the 5D0 level as a function of the concentration of Eu3+ ion have been found and is comparable to other reported for Eu3+ doped borate, phosphate glasses and higher than that for the tellurite glasses. The thermal properties such as glass transition, crystallization and melting temperatures of the Eu3+ glasses were studied through the DSC traces in the temperature range of 30−1200 °C at a heating rate of 10 °C per minute. The change in optical properties with the variation of Eu3+ ion concentration have been discussed and compared with similar results.

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