White light emission from Dy³⁺-doped ZnO + Bi₂O₃ + BaF₂ + B₂O₃ + TeO₂ glasses: Structural and spectroscopic...

The ZnO + Bi₂O₃ + BaF₂ + B₂O₃ + TeO₂ (ZnBiBaBFTe) host glass was prepared by melt quenching technique with the aim of achieving white light emission from Dy³⁺ ions. Their structural and spectroscopic properties were systemically investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV-Visible absorption, emission spectra and decay times. Judd-Ofelt (JO) parameters (Ω_λ) evaluated from absorption spectrum were utilized to calculate the radiative parameters for ⁴F_9/2 level of Dy³⁺ ions. The optical band gap energy of as-prepared glasses were calculated for the indirect, (αhυ)^1/2 and direct, (αhυ)2 allowed transitions. The emission spectra of Dy³⁺:ZnBiBaBFTe glasses showed two intense peaks at 575 nm (⁴F_9/2→⁶H_13/2) and 481 nm (⁴F_9/2⁶H_15/2) upon 386 nm excitation. The highest emission intensity was observed at 1.0 mol% of Dy³⁺ for ⁴F_9/2→⁶H_13/2 transition and the results are used in conjunction with lifetime measurements to derive spectroscopic parameters for the stimulated emission cross-section (25.2 × 10^-22 cm²), gain bandwidth (5.86 × 10^-28 cm³), and favourable quantum efficiency (74.2%). Moreover, white light can be realized with a CIE coordinates by adjusting the concentration of Dy³⁺ ions in ZnBiBaBFTe host glass. Efficient spectroscopic values and realizable white lighting in Dy³⁺-doped ZnBiBaBFTe glasses may have potential applications in laser illumination devices.