Characterization of Eu3+-doped fluorophosphate glasses for red emission

Fluorescence spectra and decay curves of the 5D0 level for different concentrations of Eu3+ (4f6) ions in K–Ba–Al fluorophosphate glasses have been measured at room temperature and are analyzed. The Judd–Ofelt intensity parameters Ω2 and Ω4 have been determined from the intensity ratios of emission peaks corresponding to 5D0 → 7FJ (J = 2 and 4) to 5D0 → 7F1 transitions for 1.0 mol% glass. The intensity parameters thus obtained are in turn used to calculate the radiative properties of the fluorescent levels of Eu3+ ions. Second and fourth rank crystal-field parameters have been evaluated by assuming a C2V site symmetry for the local environment of Eu3+ ions to estimate the crystal-field strength experienced by Eu3+ ions in the present host. The decay profiles of the 5D0 → 7F2 transition of Eu3+ ions in the present glasses are found to be single exponential for all the studied Eu3+ ion concentrations. A marginal increase in lifetime of the 5D0 level has been noticed with Eu3+ ion concentration up to 2.0 mol% and then the lifetime marginally decreases for higher Eu3+ ion concentrations.