Structural, thermal, optical properties and simulation of white light of titanium-tungstate-tellurite glasses doped with dysprosium

Structural, thermal, optical properties and simulation of white light of Dy3+-doped tellurite glasses of composition TTWD: (75 - x)TeO2 - 10TiO(2) - 15WO(3) - xDy(2)O(3) (x = 0, 0.1, 0.5, 1.0 and 2.0 mot%) were investigated. Raman spectra revealed that the glass contains TeO4, TeO3, WO4 and WO6 units. Differential scanning calorimetry (DSC) measurements were carried out to measure the glass transition temperature of all the glasses. From the optical absorption spectra, luminescence spectra and using the Judd-Ofelt (JO) analysis, we estimated the radiative transition probabilities, emission cross-sections, branching ratios and radiative lifetimes. The decay curves at lower concentrations are exponential while they show a non-exponential behavior at higher concentrations (<= 0.5 mol%) due to energy transfer processes. The effective lifetime for the F-4(9/2) level decreases with increase in Dy2O3 concentration for the glasses under investigation. The non-exponential decay curves could fit well to the Inokuti-Hirayama (IH) model with S = 6, indicating that the nature of interaction responsible for energy transfer is of dipole-dipole type. Simulation of white light is examined with varying concentration and the results indicate that these glasses are suitable for white light emitting diode applications. (C) 2013 Elsevier Ltd. All rights reserved.