Judd–Ofelt and luminescence study of Dysprosium-doped lithium borosilicate glasses for lasers and w-LEDs

The effect of Dysprosium concentration has been studied in glasses of the system 30 SiO2 + 30 Li2O + (40−x) B2O3 + x Dy2O3 glass system where x = 0.5, 1, 2.5, 5 and 10 mol%. FT-IR studies were performed to understand the functional groups of the network involved in the host glass. The optical band gap is found in the range of 3.84–3.5 eV. From the absorption spectra, the experimental data were compared with the theoretical data computed by Judd–Ofelt theory. Nephelauxetic ratio (β) and bonding parameters (δ) computed using the absorption spectrum. The Judd–Ofelt parameters (Ω2, Ω4, and Ω6) obtained demonstrates the covalent and asymmetric nature of dysprosium ions. From the visible emission spectra, the intensity ratios were calculated from yellow to blue and the relative differences were discussed based on the concentration of Dy3+ ions. CIE chromaticity coordinates were calculated for all glass samples. A CIE chromatogram shows a glass containing 0.5 mol% Dy2O3 with color coordinates X = 0.32 and Y = 0.33 with the highest emission intensity. These glasses have great potentials for lasers and white LEDs (Light-Emitting Diode) applications.