Spectroscopic properties and Judd-Ofelt analysis of Eu3+ doped barium bismuth fluoroborate glasses

This paper reports the preparation and characterization of europium doped barium bismuth fluoroborate glasses (Eu3+: BBFB) prepared by conventional melt quenching technique. The structural properties were investigated by X-ray diffraction spectra which confirm the amorphous nature of the prepared glass. Optical properties of the glasses were studied by the optical absorption, emission and decay curve measurements. Nephelauxetic ratio (beta) and bonding parameters (delta) were calculated from the absorption spectra to examine the nature of the bonding between the Eu3+ ion and its surrounding ligands. The band gap and Urbach energy of the glasses were determined from the absorption spectra to study the electronic band structure. A band gap value varies inversely with the Urbach energy values. The Judd-Ofelt intensity parameters were determined from the least square fit analysis. In the luminescence spectra, predominant high intense radiation, shows at D-5(0)-> F-7(2) transition of Eu3+ ion, is observed around 610 nm. The Judd-Ofelt intensity parameters were used to analyse the transition probability (A(R)), branching ratio (beta(R)), radiative lifetime (tau(R)) and stimulated emission cross-section (sigma(E)(P)) for all the glasses. The colour chromaticity CIE coordinates have been calculated from the emission spectra and characterized through Commission International de I'Eclairage (CIE) 1931 diagram. The decay analysis D-5(0)-> F-7(2) transition exhibits single exponential behavior for all the glasses. The higher value of the stimulated emission cross-section, at 612 nm, confirms that the prepared glass is a potential candidate for red colour laser emission applications.