Influence of sesquioxides on fluorescence emission of Yb3 + ions in PbO–PbF2–B2O3 glass system

Yb3 + ions doped lead oxyfluoro borate glasses mixed with varying concentrations of three interesting sesquioxides (viz., M2O3 = Al2O3, Sc2O3, Y2O3) were synthesized. The emission spectra of each series of glasses were recorded and characterized as a function of concentration of sesquioxides. The luminescence spectra of the three series of glasses excited at 970 nm have exhibited intense band in the NIR region corresponding to 2F5/2 → 2F7/2 transition. The emission spectra of all the three series of glasses found to be partially overlapped with the absorption band. The comparison of Stokes shift indicated the highest value for Y2O3 mixed glasses. From these spectra, the absorption and emission cross-sections and also life time of 2F5/2 level of Yb3 + ions have been evaluated. The luminescence cross section is found to be the highest for Y2O3 mixed glasses among the three series of the glasses studied. The reasons for such variations have been discussed in the light of varying degree of structural modifications at the vicinity of Yb3 + ions in the glass network with the support of IR spectral results of these glasses.