De-quenching influence of aluminum ions on Y/B ratio of Dy3+ ions in lead silicate glass matrix

Emission features of Dy3+ ions were characterized as a function of Al2O3 concentration in lead silicate glasses. The emission spectra exhibited conventional blue, yellow, orange and red emission bands due to 4F9/2?6H15/2, 6H13/2, 6H11/2 and 6H9/2 transitions of Dy3+ ions, respectively. The intensity of all these bands exhibited increasing trend with increase in the concentration of Al2O3 and this increase was attributed to decrease of luminescence quenching due to declusterization of Dy3+ ions by Al3+ ions in the glass network. From the emission spectra, the radiative parameters viz., spontaneous emission probability A, the total emission probability AT, the radiative lifetime τρ, the fluorescent branching ratio b, of different transitions originated from 4F9/2 level of Dy3+ ions were evaluated. The Y (I4F9=2→6H11/2)=B(I4F9/2→6H15/2) integral emission intensity ratio of Dy3+ ions evaluated from the luminescence spectra, showed decreasing trend with increase in the concentration of Al2O3. The decrease of this ratio is explained basing on structural modifications taking place in the vicinity of the Dy3+ ion in the glass matrix. The CIE color coordinates for three glasses were evaluated and found to be in the yellow region.