Compositional dependence of structural, thermal and luminescence properties of germanate-phosphate glasses singly doped with Tm3+ and Pr3+ ions

In this paper, the influence of glass composition on structural, thermal, and luminescence properties of germanate-phosphate glasses doped with Tm 3+ and Pr 3+ ions was investigated. Based on infrared (IR-ATR) and Raman spectroscopy, changes in the local glass structure were found to be related to the glass composition. The effect of glass former concentration (P 2 O 5 and GeO 2 ) on the thermal stability of the systems was evaluated using differential scanning calorimetry (DSC). The visible emissions of Tm 3+ and Pr 3+ ions were observed in all glasses. The red-to-blue (R/B) intensity ratios for Tm 3+ ions indicated that glass composition has no significant effect on luminescence intensity. In contrast, the orange-to-blue (O/B) intensity ratios for Pr 3+ ions shown an increase in the blue emission. Furthermore, all glasses exhibited near-infrared emissions regardless of glass composition. The full width at half maximum (FWHM) and luminescence lifetimes, for the 3 F 4 (Tm 3+ ) and 1 D 2 (Pr 3+ ) levels, were also determined. These systematic investigations indicate that an appropriate concentration of glass formers enables the development of systems with improved emission properties. The germanate-phosphate glasses may be promising materials for blue (Tm 3+ ) and red (Pr 3+ ) visible emitters, or near-infrared broadband emitters operating within the second and third biological windows.