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Structural and optical studies of Eu 3+ ions in alkali borate glasses
Author(s) -
Marimuthu K.,
Surendra Babu S.,
Muralidharan G.,
Arumugam S.,
Jayasankar C. K.
Publication year - 2009
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200824198
Subject(s) - europium , luminescence , ion , photoluminescence , boron , analytical chemistry (journal) , radiative transfer , alkali metal , materials science , emission spectrum , absorption (acoustics) , chemistry , spectral line , physics , optics , optoelectronics , organic chemistry , chromatography , astronomy , composite material
Europium‐doped borate‐based glasses (Eu 3+ :MBE (M = Na, K and Na + K)) have been prepared by a melt quenching technique and characterized optically. FTIR spectra and XRD patterns were used to analyze the glass structure. The spectroscopic properties such as optical absorption and photoluminescence spectra and decay time measurements for the 5 D 0 level of Eu 3+ ions were obtained. A strong red fluorescence is observed from the 5 D 0 level of Eu 3+ ions in these glasses. Judd–Ofelt (JO) parameters have been evaluated from the luminescence intensity ratios of 5 D 0 → 7 F J ( J = 2 and 4) to 5 D 0 → 7 F 1 transitions. These parameters have been used to derive radiative properties such as transition probabilities, branching ratios, radiative lifetimes and peak stimulated emission cross sections for the 5 D 0 → 7 F J transitions. The relative luminescence intensity ratio ( R ) of 5 D 0 → 7 F 2 to 5 D 0 → 7 F 1 transitions has been evaluated to estimate the local site symmetry around the Eu 3+ ions. Relatively higher values of R and the JO parameter Ω 2 for the Eu 3+ :MBE glasses suggest a lower symmetry for Eu 3+ ions and a higher Eu–O covalence. Decay curves of the 5 D 0 level of Eu 3+ ions have been measured by monitoring the 5 D 0 → 7 F J transition (at around 612 nm) at room temperature. The experimental lifetime of the 5 D 0 level in these glasses is found to be lower than Eu 3+ ‐doped phosphate glasses and comparable to or higher than Eu 3+ ‐doped niobium phosphate or tellurite glasses. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)