Energy Transfer and Spectroscopic Investigation of Dy₂O₃ Doped Li₂O–BaO–GdF₃–SiO₂ for White Light LED

Abstract: LGFDy glasses doped with Dy₂O₃ (0.1, 0.5, 1.0, 1.5 and 2.0 mol %) were synthesised by conventional melt quenching method and various properties are studied by absorption, Judd–Ofelt analysis, photoluminescence, X-ray excited luminescence, decay curve and CIE color chromaticity measurement. Judd-Ofelt parameters (Ω₂, Ω₄ and Ω₆) are valuated form JO theory in order to estimate the radiative parameters of the Dy³⁺ ion excited states. For white light emission, Yellow/Blue (Y/B) ratio and CIE color coordinates for glasses under study are measured from the emission spectra. The energy transfer from Gd³⁺ to Dy³⁺ ions has been studied by exciting the glass with 275 nm photon. The higher value of σ (λ_p) and β_R for ⁴F_9/2 → ⁶H_13/2 transition indicates its more potential use in laser application in yellow region. The correlated color temperature for LGFDy glasses is found to be 4264 K. The decay profile of fluorescent level ⁴F_9/2 for different concentration of Dy³⁺ ions in the present glasses changes to non-exponential from single-exponential for higher concentration (≥0.5 mol %) of Dy³⁺ ions. Thus the chemical composition of glass and dopant (Dy³⁺ ions) concentration strongly influence the energy transfer mechanism. The lifetime non-exponential behavior is well fitted to IH-model for S = 6. The quantum efficiency for LBGFDy05 glass is found to be 86%. The systematic investigation signifies the potential of the studied LGFDy glasses for the laser and white light generation application.