Effect of TiO2 on the thermal and optical properties of Er3+/Yb3+ co-doped tellurite glasses for optical sensor

Abstract

Er3+/Yb3+ co-doped tellurite glasses (83-x)TeO2–10Nb2O5–5Al2O3–xTiO2–1Er2O3–1Yb2O3 where x=0, 2.5, 5, 7.5 and 10 mol% were fabricated by the conventional melt quenching technique. The structural, thermal and optical properties of the tellurite glasses were studied in dependence of the TiO2 concentration. All samples exhibit an amorphous structure which was modified by the introduction of TiO2 according to the X-Ray Diffraction (XRD) and Raman spectroscopy results. Differential scanning calorimetry (DSC) shows that the glass transition temperature and thermal stability increases with the addition of TiO2. The highest value of glass transition temperature (Tg) was 722 K which is one of the highest values found in the literature. On the other hand, the thermometric properties of two representative samples were studied by the fluorescence intensity ratio (FIR) technique. The maximum sensor sensitivity was 4.48 x 10–3 *K–1 at the 490 K temperature for sample with 5 mol% of TiO2 and 5.94 x 10–3 *K–1 at the 480 K temperature for sample with 7.5 mol% of TiO2 corresponding to 32% increase in the maximum sensor sensitivity by increasing TiO2 concentration. These results suggest that the presented host matrix is a good candidate for high temperature sensing applications.