Dy3+ doped LiCl-CaO-Bi2O3-B2O3 glasses for WLED applications

Dy3+ doped calcium bismuth borate glasses were synthesized in the composition range of xLiCl-(30 − x)CaO-20Bi2O3-50B2O3 + 1 mol% Dy2O3 (x = 0, 2, 5, 7, 10 and 15 mol%, LC0, LC2, LC5, LC7, LC10 and LC15 respectively) using conventional melt-quench technique. Broad XRD profiles confirmed non-crystalline nature of synthesized compositions. The compositional dependencies of structural changes (using FTIR spectra), thermal behavior (using DSC thermographs) and optical band gap (using UV-Vis-NIR spectra) were discussed. Photoluminescence (PL) excitation spectra recorded at 577 nm yielded six different excitation peaks belonging to Dy3+ ions. The PL emission spectra recorded at 451 nm were analyzed to extract different light emission parameters viz. Y/B ratio, color coordinates, correlated color temperature (CCT) following CIE 1931 chromaticity diagram. The emission colors were found to lie in white light region and lies very close to standard white light emission. The CCT of sample LC10 (5335 K) is closest to CCT of standard white light (5615 K) which depicted the optimized concentration of LiCl for application of these glasses in WLED application.