Influence of sesquioxides on luminescence features of Nd3+ ions in PbO–PbF2–B2O3 glass system

The emission characteristics of Nd3+ ions in PbO–PbF2–B2O3–M2O3 (M=Y, Sc, Al) glasses were studied as a function of M2O3 concentration. The IR spectral investigations have indicated that the network of the glass mixed with Y2O3 is more depolymerized when compared with other two sesquioxides. The optical absorption, luminescence spectra and fluorescence decay curves of these glasses were studied as functions of concentration of M2O3. The luminescence spectra of these glasses have exhibited three NIR bands corresponding to the transitions 4F3/2→4I9/2, 4F3/2→4I11/2 (at 1.06 μm) and 4F3/2→4I13/2. A clear enhancement in the luminescence emission corresponding to these transitions has been observed with increase in the concentration of M2O3 upto 8.0 mol%. The comparison of emissive characteristics of the glasses mixed with three sesquioxides indicated the highest luminescence efficiency for Y2O3 mixed glasses among the three series glasses studied. The increase of luminescence efficiency has been attributed to the possible declusterization of Nd3+ ions by M3+ ions in the glass network. The reasons for low luminescence quenching observed in case of Y2O3 mixed glasses have been explored in terms of the ionic radii of the sesqui-ions and their possible positions in the glass network.