Impact of bismuth concentration on the fluorescence properties of the bismuth borosilicate glasses

The glass samples with composition (30 SiO2-5 TeO2-1.0 Dy2O3-(65-x) B2O3-xBi2O3) where x = 5, 15, 25, 35, 45 and 50 mol% were prepared by melt quenching method. The glassy state was confirmed by the X-ray diffraction. Fourier transformation infrared, physical properties (density, ion concentration, molar volume, Polaron radius, inter-nuclear distance, refractive index, optical bandgap) absorption spectra, excitation, and emission spectra have been analyzed. The absorption spectrum shows five bands with a hypersensitive transition corresponding to 6H9/2 (7911 cm−1) at 1256 nm. The emission spectra showed two intense emission bands around 480 nm and 575 nm corresponding to the 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 transition. PL intensity decreases with increasing the Bi2O3 content. All values of the fundamental parameters (The color coordinates, Y/B ratio, and color rendering index (CRI)) are very close to the standard value for the glass samples with high Bi2O3 content.