Luminescent studies of Dy 3+ ion in alkali lead tellurofluoroborate glasses

Journal of Quantitative Spectroscopy and Radiative Transfer (Impact Factor: 2.29). 01/2011; 112(1):78-84. DOI: 10.1016/j.jqsrt.2010.08.017

ABSTRACT Dy3+-doped alkali lead tellurofluoroborate (RLTB) glasses (R=Li, Na and K) were prepared by melt quenching technique. Judd–Ofelt theory has been used to evaluate the three intensity parameters Ω2, Ω4 and Ω6 from the experimental oscillator strengths. The photoluminescence spectra obtained by the excitation wavelength of 385nm show four emission bands at 454, 483, 575 and 665nm corresponding to the 4I15/2→6H15/2 and 4F9/2→6HJ/2 (J=15/2, 13/2 and 11/2) transitions, respectively. The laser characteristic parameters like fullwidth at half maxima (FWHM), stimulated emission cross-sections (σe), optical gain parameters (σe×τexp) and gain bandwidth parameters (σe×FWHM) were determined. From the visible emission spectra, yellow to blue (Y/B) intensity ratios and chromaticity coordinates were also estimated. The lifetimes of 4F9/2 metastable state were also measured and discussed.

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    ABSTRACT: A spectroscopic investigation of zinc phosphate glass activated with 1.0, 5.0 and 10.0 mol% of Dy(PO3)3 is performed through absorption and luminescence spectra and decay times to study its potentialities for yellow laser operation upon excitation at 399 nm, which fits to the requirements of GaN LEDs. In the 1.0 mol% Dy(PO3)3-doped glass a quantum efficiency of 80 ± 5% was estimated for the dysprosium 4F9/2 level luminescence, the 4F9/2 → 6H13/2 yellow emission shows greater intensity than the 4F9/2 → 6H15/2 blue emission, as well as a very high optical gain, which might make this glass phosphor a promising gain medium for solid state yellow laser pumped by GaN LEDs.
    Optical Materials 11/2014; 38. DOI:10.1016/j.optmat.2014.10.024 · 2.08 Impact Factor
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    ABSTRACT: Zinc Alumino Bismuth Borate (ZnAlBiB) glasses doped with terbium (Tb3+) ions with a chemical composition 20ZnO–10Al2O3–(10−x)Bi2O3–60B2O3−xTb2O3 (x=0.1, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 mol%) were prepared by a conventional melt quenching method and studied their optical absorption, photoluminescence and decay spectral properties. The Judd–Ofelt (J–O) parameters evaluated from the experimental oscillator strengths were used to measure the radiative properties for the prominent luminescent transitions of Tb3+ ions such as 5D4→7F6, 7F5, 7F4 and 7F3. The effect of Tb3+ ion concentration on the luminescence process observed in the visible region was discussed in detail. The emission spectra recorded for all the ZnAlBiB glasses doped with Tb3+ ions, show an intense peak in green region at 542 nm. The stimulated emission cross-section, branching ratios and quantum efficiency values evaluated for green emission (5D4→7F5) suggests the utility of these glasses for green luminescence applications. It was found that, within the concentration range investigated, 2.5 mol% of Tb3+ doped ZnAlBiB glass is most suitable for green luminescence applications at 542 nm in principle.
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    ABSTRACT: A new series of white light emitting Dy(3+) doped Lead tellurofluoroborate glasses have been prepared and their spectroscopic and energy transfer behavior were explored through analyzing XRD, FTIR, Raman, SEM, EDAX, optical absorption, photoluminescence and lifetime measurements. The fundamental stretching of the various borate and tellurite networks were identified using FTIR and Raman spectral analysis. The bonding parameter studies reveal the ionic nature of the DyO bond in the present glasses. The Judd-Ofelt (JO) intensity parameters determined from the absorption spectra have been used to investigate the nature of bonding and symmetry orientation of the Dy-ligand field environment. The luminescence intensity increases with increasing Dy(3+) ion concentration up to 0.5wt%, beyond that luminescence quenching is observed. The JO parameters have been used to determine the transition probability (A), stimulated emission cross-section (σP(E)), radiative lifetime (τR) and branching ratios (βR) for the different emission transitions from the (4)F9/2 excited level. The higher σP(E) and βR values of the (4)F9/2→(6)H15/2 and (4)F9/2→(6)H13/2 transitions suggest the possible laser action in the visible region. The Y/B ratio, CIE chromaticity color coordinates (x, y) and Color correlated temperature (CCT) were also estimated from the luminescence spectra for different concentration as well as pumping wavelengths. The x, y chromaticity color coordinates fall within the white light region and the white light can be tuned by varying the excitation wavelengths. The lifetime of the (4)F9/2 excited state were measured and is found to decrease with increasing Dy(3+) ion content. The non-exponential behavior is predominant in higher Dy(3+) ion content glasses and is due to the efficient energy transfer between Dy(3+)Dy(3+) ions. The decay curves were fitted to the Inokuti-Hirayama (IH) model to understand the nature of energy transfer. Among the prepared glasses, 0.5DPTFB glass possesses higher A,βR,σP(E),η values and is suggested for lasers and WLED applications. Copyright © 2014 Elsevier B.V. All rights reserved.
    Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 11/2014; 136PC:1684-1697. DOI:10.1016/j.saa.2014.10.067 · 2.13 Impact Factor


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May 28, 2014