Dy3+: B2O3-Al2O3-ZnF2-NaF/LiF oxyfluoride glasses for cool white or day white light-emitting applications

Structural, thermal and optical characteristics of 0.5 mol% Dy3+-doped oxyfluoride zinc alumino borate glasses were studied by XRD, FTIR, DSC, optical absorption, and luminescence approaches. All FTIR spectra indicate the presence of functional groups like BO4 and BO3 units, and AlO6 groups. Dy3+ shows emission bands at 483 nm (F-4(9/2) -> H-6(15/2) transition, blue), 575 nm (F-4(9/2) -> H-6(13/2) transition, yellow), and 663 nm (F-4(9/2) -> H-6(11/2) transition, weak red), respectively, under 350 nm excitation. Among all samples, 54.5B(2)O(3)-5Al(2)O(3)-10ZnF(2)-30NaF-0.5Dy(2)O(3) glass exhibits the highest intensity for all observed emission bands. The emission spectral data were used to compute yellow/blue (Y=B) ratios, color chromaticity coordinates (x, y), correlated color temperatures (CCT), D-uv, and color purity (CP) of the samples. The deduced color coordinates (0.345, 0.350), 5003 K CCT at-0.001 D-uv with 9% color purity for 54.5B(2)O(3)-5Al(2)O(3)-10ZnF(2)-30NaF-0.5Dy(2)O(3) sample hints it as a potential candidate for WLEDs application.