Physical and structural properties of dysprosium ion doped phosphate glasses

Magnesium-zinc-sulfophosphate glasses with the composition of (60-x)P2O5-20MgO-20ZnSO(4)-xDy(2)O(3) (x = 0.0, 0.5,1.0, 1.5 and 2.0 mol%) were prepared via the melt-quenching technique. Xray diffraction (XRD) patterns were utilized for characterizing the prepared samples. Using the optical absorption spectra, the values of Urbach energy (Delta E), direct (E-opt(dir)), and indirect band gaps (E-opt(indir) ), dielectric constant (epsilon), refractive index (n), reflection loss (R), molar reflection (R-M), and molar polarizability (a(m)) were calculated for each of the samples. According to the obtained results, the density of studied glasses increased from 2.6619 to 2.7676 g cm(-3) by adding Dy3+ concentration, while molar volume decreased from 56.6258 to 56.1657 cm(3) up to 1 mol% Dy2O3 and then increased for 1.5 mol% Dy3+. It seems that some structural rearrangements have been developed by increasing the Dy3+ content of the phosphate network. In coincidence with the increasing Dy2O3 concentration from 0.5 to 1.5 mol%, the optical energy band gap (E-opt) increases linearly from 4.0925 eV to 4.2080 eV which may be attributed to the formation of NBOs. The greater value of Urbach energy in PZSMDy1.5 glass implies its more disorder. The values of molar polarizability (a(m)), molar reflection (R-m), reflection loss (R), and dielectric constant (epsilon) decrease with raising Dy3+ content up to 1.5 mol% and increase subsequently.