Spectroscopic investigation on Dy3+ ions in borate glasses for photonic applications

The samples were prepared and characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR), optical absorption, photoluminescence (PL), and decay time measurements on borate-based glasses with compositions of (60-Y) B2O3 + 20 CaO + 20 NaF + Y Dy2O3 (Y = 0.2, 0.4, 0.6, 0.8, and 1.0%). Using the JO theory, the Judd–Ofelt (JO) intensity parameters (Ωλ, λ = 2, 4, and 6) for BCNFDy glasses were computed. The emission bands have been used to determine the chromaticity color coordinates (x, y), yellow to blue (Y/B) intensity ratios, stimulated emission cross-sections (σ(λp)), effective band widths (Δλeff), and others. By observing the strong 4F9/2 → 6H15/2 transition (486 nm), the decays from the Dy3+ ions 4F9/2 level have been calculated. Due to the quenching process, it is discovered that the experimental lifetimes (τexp) shorten as the quantity of Dy3+ ions increases. At lesser concentrations, the lifetime curves are absolutely single exponential and they step by step change to non-exponential at larger Dy3+ ion concentrations. A dipole–dipole type of energy transmission between the donor and acceptor is shown by how well the Inokuti–Hirayama (IH) model matches the non-exponential decay time curves for S = 6. The results obtained point to the usefulness of the glasses for possible future applications in w-LED technology.