Structural and luminescence properties of Dy3+ ion in strontium lithium bismuth borate glasses

Different concentrations of dysprosium doped strontium lithium bismuth borate (SLBiB) glasses were synthesized by the conventional melt quenching method and characterized through X-ray diffraction, Raman, absorption and visible luminescence spectroscopies. These Dy3+ doped glasses are studied for their utility for white light emitting diodes. X-ray diffraction studies revealed amorphous nature of the studied glass matrices. Coexistence of trigonal BO3 and tetrahedral BO4 units was evidenced by Raman spectroscopy. From the absorption spectra, Judd-Ofelt (J-O) intensity parameters, Omega(lambda) (lambda = 2, 4 and 6), have been calculated. The hypersensitivity of the transition, H-6(15/2) -> F-6(11/2) of Dy3+ has been discussed based on the magnitude of Omega(2) parameter. Using J-O intensity parameters, several radiative properties such as spontaneous transition probabilities (A(R)), radiative branching ratios (beta(R)) and radiative lifetimes (tau(R)) have been determined. From the emission spectra, a strong blue emission that corresponds to the transition, F-4(9/2) -> H-6(15/2), was observed and it also shows combination of blue, yellow and red emission bands for these glasses. In addition to that, white light emission region have been observed from these studies. (C) 2011 Elsevier B.V. All rights reserved.