Optical Properties of Erbium doped Molybdenum Tellurite Glasses

The glasses with the composition of xEr 2 O 3 -5AgCl- 15MoO 3 -(80-x) TeO 2 (x = 0, 0.5 and 1 mol%, named as SMT0, SMT1 and SMT2, respectively) were synthesized using conventional melt quenching method and their optical properties were investigated through UV-Visible spectrophotometer. Density and molar volume values of the glass samples were estimated, their values were found in the range from 5.52 to 5.64 g/cm 3 and 27.737 to 28.689 cm 3 , respectively. The UV absorption spectra were recorded at room temperature in the wavelength range 200-1100nm. From the absorption edge data, it is found that both the direct and indirect type transitions may takeplace. The direct and indirect band gap values are ranging from 1.92 to 2.29 eV and 1.24 to 1.77 eV, respectively. Also, the Urbach energy (E tail ) values were determined and their values are ranging from 0.33 to 0.54 eV. These obtained E tail values are well matched with amorphous semiconductors (0.046 to 0.66 eV)

Electronic-Ionic Conductivity of Lithium- Vanado- Phosphate Glasses

The new glassesof glass system x Li 2 O-50 V 2 O 5 -(50-x) P 2 O 5 were prepared by using conventional melt quenching method. The densities of these glasses have been measured by Archimedes method and corresponding molar volumes have also been calculated. The conductivity of these glasses was measured as a function of temperature and composition. The variations of conductivity versus temperature follow Arrehenius type relationship. Conductivity decreases with increasing Li 2 O content and increase with increasing temperature. The calculated activation energy decreases up to 15mol% of Li 2 O, it increases from 15mol% to 30 mol% of Li 2 O and again it suddenly drops at 40 mol% of Li 2 O. This may be due to structural changes in glass network and these glasses exhibit both electronic and ionic conductivity

Optical Properties of Zinc-Vanadium Glasses Doped with Samarium Trioxide

Zinc–vanadium glasses doped with samarium oxide having the chemical composition Sm2O3(x) ZnO(40-x)V2O5(60)(where x = 0·1–0·5 mol%) were prepared by melt quenching method. The density of these glasses was measured by Archimedes method; the corresponding molar volumes have also been calculated. The values of density range from 3·7512 to 5·0535 gm/cm3 and those of molar volume range from 28·3004 to 37·6415 cm-3. The optical absorbance studies were carried out on these glasses to measure their energy bandgaps. The absorption spectra of these glasses were recorded in UV–Visible region. No sharp edges were found in the optical spectra, which verify the amorphous nature of these glasses. The calculated optical bandgap energies of these glasses were found to be in the range of 0·3173–0·6640 eV. The refractive index and polarizability of oxide ion have been calculated by using Lorentz–Lorentz relations. The values of refractive index range from 1·1762 to 1·2901 and those of polarizability of oxide ion range from 1·6906 × 10-24 to 2·2379 × 10-24 cm

Optical Properties of Zirconium Doped Sodium-Boro-Zinc Fluoride Glasses

Effect of Zirconium doped sodium borate glasses with zinc fluoride and without zinc fluoride glasses were prepared individually by conventional melt quench method. All the Samples were analyzed using certain measurements like UV-Visible and Photoluminescence. UV-Visible spectra evidences that after 1mol% incorporation to glass matrix there exist 3F2-3P1 transition due to Zr2+ ions in both Zr:Zf glass series. Further; using Tauc's equation direct and indirect band gaps were estimated for all samples. Upon the excitation 365nm and 383nm the PL studies were carried out to know the possible transitions and the role of Zirconium in both glass series for the same CIE diagram was done

Synthesis and Structural Characterization of Niobium Doped Lead-Telluride Glass-Ceramics

The basic glasses with composition (70-x) TeO2-30PbO-xNb2O5 (where x=0.1 mol % and 0.2 mol %) were prepared by melt quenching method and heat treated at 2800C for 30 min. The samples becoming glass ceramics was confirmed by SEM. The XRD parameters such as crystallite size of these glass ceramics decreases as increase the impurity and is the order of 184-109A0 . However, micro strain (ε) and dislocation density (δ) increases. Glass transition and thermal stability estimated from DSC measurements and it has been found that both increase with increasing of impurity. Infrared Absorption spectra were measured for TeO2 glass and glass ceramic doped with Nb2O5. The recorded bands attributed to the different modes of vibration and stretching of Te-O band. Optical Absorption spectra of TeO2-PbONb2O5 system shows that the absorption edge has a tail extending towards the lower energies and shifts towards for higher energies for rare earths-doped glass-ceramics. The degree of the edge shift was found to depend on the structural rearrangement and the relative concentrations of the glass basic units. The general appearance of the absorption spectra of these rare earth doped TeO2 glasses are similar to the spectra observed for other glasses doped with the same kind of rare earth oxides

Optical properties of samarium doped zinc-phosphate glasses

Samarium doped zinc-phosphate glasses having composition Sm2O3 (x)ZnO(60-x) P2O5 (40) (where x=0.1-0.5 mol) were prepared by melt quenching method. The density of these glasses was measured by Archimedes method; the corresponding molar volumes have also been calculated. The values of density range from 3.34 to 3.87 gm/cm3 and those of molar volume range from 27.62 to 31.80 cm-3. The optical absorbance studies were carried out on these glasses to measure their energy band gaps. The absorption spectra of these glasses were recorded in UV-visible region. No sharp edges were found in the optical spectra, which verifies the amorphous nature of these glasses. The optical band gap energies for these glasses were found to be in the range of 2.89-4.20 eV. The refractive index and polarizability of oxide ion have been calculated by using Lorentz-Lorentz relations. The values of refractive index range from 2.13 to 2.42 and those of polarizability of oxide ion range from 6.51Ã10-24 to 7.80Ã10-24 cm3. © 2007 Elsevier Ltd. All rights reserved

Silver lead borate glasses doped with europium ions for phosphors applications

Europium (Eu3+) doped silver lead borate glasses with the composition of xEu2O3�(1 � x)Ag2 O�29PbO�70B2O3 (x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5 mol) have been successfully prepared by conventional melt quenching method. Thermal, structural and luminescence properties have been studied using thermograms, transmittance, excitation and emission spectra. From the differential scanning calorimetry studies, the glass transition temperatures (Tg) have been investigated and their values are ranging from 449 to 458�C. The investigation of Fourier transformer infrared spectra shows the presence of boron atoms in both BO3 and BO4 units in the glass network. In addition, it was found that new structural groups were present, such as boroxyl rings, pyro and dipenta-borate. Photoluminescence spectroscopy was used to examine down conversion emission under 394 nm excitation, which exhibits five emission bands centred at 577, 590, 612, 650 and 697 nm corresponding to 5D0�7F0, 5D0�7F1, 5D0�7F2, 5D0�7F3 and 5D0�7F4 transitions of Eu3+ ions, respectively. The Commission International de I�Eclairage France 1931 chromaticity coordinates estimated from the emission spectra; it was shown that a 0.5 mol Eu2O3 doped glass is quite suitable for efficient red phosphors application. © Indian Academy of Sciences

Optical Studies of Eu3+ Ion Doped Borate Glasses

Eu3+ ion doped borate glasses were prepared by conventional melt quenching technique. Amorphous nature of the prepared glass is confirmed by XRD technique. The physical parameters like density, molar volume, polaron radius, inter-nuclear distance and field strength were calculated. The density, molar volume values were ranging from 4.150 to 4.307 g/cm−3 and 26.014 to 27.152 cm−3 respectively. The direct, indirect energy band gap and also Urbach energy were calculated. The calculated energy values were range from 3.03 to 3.179eV, 1.461 to 2.771eV and 0.443 to 1.309eV respectively. The optical parameters like refractive index, the molar refraction and polarizability were calculated using Lorentz-Lorentz relation