SPECTRAL INVESTIGATIONS OF TRIVALENT EUROPIUM (Eu3+) IONS DOPED ZnBiNaPSr OXYFLUORIDE GLASSES FOR VISIBLE PHOTONIC DEVICE APPLICATIONS.

Oxyfluoride (P2O5-Bi2O3-Na2CO3-SrCO3-ZnF2-Eu2O3) glasses of different dopant (Eu3+) ion concentrations were synthesized by the traditional melt quenching method. Optical absorption, luminescence and lifetime measurements were performed with UV-Vis and PL techniques. A total of six absorption bands were observed in the wavelength range 200-800 nm, including one intense high band at 392 nm was assigned to 7F0→5L6 transition. The covalency between the host environment and Eu3+ ion was noticed with the measured nephelauxetic ratios (β) and bonding parameters (δ). The energies of the energy band gaps (Eg) and Urbach (ΔE) were estimated from the Tauc's plots, drawn from the absorption spectra. Luminescence spectra exhibited the prominent reddish-orange emission at 612 nm due to the 5D0→7F2 characteristic transition of Eu3+ ion. The lasing (radiative) parameters of f-f transitions of the Eu3+ ion was evaluated using the Judd-Ofelt intensity parameters (Ω2, Ω4, and Ω6). The higher magnitude of branching ratios (βexp) suggests the suitability of the present glass. The decay profile for the 5D0 level of europium was recorded by monitoring the emission and excitation wavelengths 612 & 392 nm, respectively. The color temperature and purity were calculated using CIE 1931 color coordinates. The emission color band spectra have also been recorded. [ABSTRACT FROM AUTHOR]