Optical band gap studies on xPb3O4–(1−x)P2O5 lead[(II,IV)] phosphate glasses

2002 ◽  
Vol 18 (4) ◽  
pp. 367-372 ◽  
Author(s):  
M Salagram ◽  
V Krishna Prasad ◽  
K Subrahmanyam
Keyword(s):  
Band Gap ◽  
Optical Band Gap ◽  
Phosphate Glasses

Optical and structural characterization of quadruplet and quintuplet molybdenum-containing phosphate glasses

2016 ◽  
Vol 30 (18) ◽  
pp. 1650270 ◽  
Author(s):  
Ehsan Soheyli ◽  
Mohammad Hossein Hekmatshoar ◽  
Farshad Parcham
Keyword(s):  
Transition Metal ◽  
Band Gap ◽  
Absorption Edge ◽  
Transition Metal Oxides ◽  
Optical Band Gap ◽  
Glass Network ◽  
Direct Consequence ◽  
Transition Metal Ions ◽  
Phosphate Glasses ◽  
Absorption Bands

In this work, vitreous samples were prepared in two series by normal melt-quenching technique and under controlled conditions. The amorphous nature of specimens was confirmed using XRD spectra. To perform FT-IR and UV-vis studies, the thin blown films were also prepared. Different ratios of transition metals are assumed to cause depolymerization of the phosphate glass network. Infrared spectra showed absorption bands related to characteristic bonds of phosphate. The P=O bond at about 1200 cm[Formula: see text] was observed, as a direct consequence of meta-phosphate bond group. The almost unchanged peak position and intensity of P=O bond (in the presence of two transition metal ions) indicated the glass modifying nature of transition metal oxides (TMOs). The spectra of two series are almost identical, except for 890–1100 cm[Formula: see text] range, which can be attributed to presence of second TMO in the first glass series. UV-vis spectra also showed that the absorption edge, optical band gap and Urbach energy of the prepared samples are highly dependent on the kind and percentage of their reagents. The most striking result of UV-vis measurements was increasing and decreasing of optical band gap in the first and the second series with MoO3 content, respectively. The shape of the absorption edge (a plot of [Formula: see text] versus [Formula: see text]) demonstrated the indirect nature of the band gap in the prepared specimens.

scholarly journals Optical Properties of Silver-Vanadium-Phosphate Glasses

2017 ◽  
Vol 16 (1) ◽  
pp. 1-7
Author(s):  
B Eraiah
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Band Gap ◽  
Room Temperature ◽  
Optical Band Gap ◽  
Phosphate Glasses ◽  
Vanadium Phosphate ◽  
Tauc Plot ◽  
Uv Visible ◽  
Oxide Ions

The glasses with the composition of xAg2O-50V2O5-(50-x)P2O5 (where x = 5,10,15,20,30 and 40 mol%) were synthesized using melt quenching technique and their optical properties were carried out through UV-Visible spectrophotometer. The absorption spectra of these glasses were recorded at room temperature in the wavelength range 200-1100nm. The optical band gap energies were calculated using Tauc plot. The calculatedenergy band gap values are ranging from 2.075 to 2.834 eV. The refractive index and polarizabilities of oxide ions have been calculated using Lorentz-Lorentz relation. The calculated refractive index and polarizabilities of these glasses in the range of 2.443 to 2.703 and 9.8877×10-24 to 13.590×10-24cm3.

scholarly journals The Tungsten Oxide Within Phosphate Glasses to Investigate the Structural, Optical and Shielding Properties Variations

2021 ◽  
Author(s):  
mohammed sadeq ◽  
B.O. El-bashir ◽  
Aljawhara H. Almuqrin ◽  
M.I. Sayyed
Keyword(s):  
Band Gap ◽  
Optical Band Gap ◽  
Visible Region ◽  
Average Density ◽  
Radiation Shielding ◽  
Phosphate Glasses ◽  
Blue Color ◽  
Color Transformation ◽  
Dark Blue ◽  
Average Molar Volume

Abstract We prepared a series of sodium phosphate glasses by changing WO3/P2O5 content and investigated structure optical and radiation shielding features as a function of glass composition. The average density (ρexp) and was found to increase gradually from 2.49 to 3.07 g/cm3 while the average molar volume values reduced from 47.37 to 44.28 cm3/mol with WO3 addition. Also, the average field strength was also computed and found to increase with increasing WO3. The study of optical absorption spectra reveals that, the absorption peaks in the visible region become higher compared to the peaks In the UV region. This observation is accompanied with a color transformation of glasses from light to dark blue color, with more WO3 adding. The existence of pentavalent tungsten state (W5+) is identified by this blue color. with WO3 addition an absorption band at around at 350–390 nm is appeared. Moreover, this band is overlapped with Urbach edge, which regularly produces an artificial edge-like feature at ~400 nm. A detailed deconvolution protocol is required for an appropriate understanding of these spectra and unravelling the hidden Urbach edge. Our analysis shows that, with increasing WO3/P2O5 content, the optical band gap decreases. This behavior can be elucidated in terms of lower band gap of W (2.7 eV) than that of P2O5 (8.5 eV) and the high polarizing power W. Further, the radiation shielding parameters were investigated for the prepared glasses. WO3 addition improves these shielding parameters against radiation. Where, upon the increase of WO3 concentration, the LAC of glass material increases which leads to a decrease in HVL value. Then it is deducible that the amount of WO3 in this glass sample has an important impact on the shielding capability at lower energy values and has a slight impact at higher energy values.

EFFECT OF B2O3 ON PHYSICAL AND OPTICAL PROPERTIES OF ZINC PHOSPHATE GLASSES

2006 ◽  
Vol 20 (26) ◽  
pp. 1637-1643
Author(s):  
M. ALTAF ◽  
M. A. CHAUDHRY ◽  
M. TARIQ BHATTI
Keyword(s):  
Band Gap ◽  
Optical Band Gap ◽  
Zinc Phosphate ◽  
Mass Density ◽  
Band Gap Energy ◽  
Phosphate Glasses ◽  
Exponential Dependence ◽  
Amorphous Nature ◽  
Sharp Edges ◽  
Band Tailing

Zinc-phosphate glasses with the addition of B 2 O 3 were prepared by using the melt quench technique. These glasses had a mol% composition of 30 ZnO -x B 2 O 3 - (70-x) P 2 O 5. The quantity x had values of 10–40 mol%. The mass density of these glasses was found to be in the range of 2.4912–3.0142 g/cm3. The oxygen packing density and molar volume were estimated to lie in the range 192.385–286.026 g-atom/liter and 46.78–31.46 cm3 respectively. The absorption spectra of these glasses were recorded in the range of 190 to 1100 nm. No sharp edges were found in the optical spectra, which confirms the amorphous nature of these glasses. The optical band gap energies were determined to be in the range of 2.40–3.00 eV. A decreasing behavior in optical band gap energy was seen due to the increasing concentration of B 2 O 3. The extent of band tailing was worked out from the Urbach plots, which showed an exponential dependence of absorption coefficients on photon energies.

scholarly journals Optical Characteristics of Some Binary and Ternary Phosphate Glasses

1995 ◽  
Vol 48 (5) ◽  
pp. 887 ◽  
Author(s):  
M Ashraf Chaudhry ◽  
Anwar Manzoor Rana ◽  
M Altaf ◽  
M Shakeel Bilal
Keyword(s):  
Band Gap ◽  
Optical Band Gap ◽  
Glass Composition ◽  
Visible Region ◽  
Band Gap Energy ◽  
Phosphate Glasses ◽  
Optical Absorption Spectra ◽  
Gap Energy ◽  
Sharp Edges ◽  
Uv Visible

The optical absorption spectra of some binary and ternary phosphate glasses are studied in the UV-visible region by using a spectrophotometer. The observed absorbance versus wavelength curves do not show any sharp edges in these glasses. The optical band gap energies are found to depend significantly on glass composition. The optical band gap energy is found to increase with increasing ZnO content in binary and ternary glass systems.

A Study of Electron Paramagnetic Resonance and Optical Absorption Spectra of VO2+ Ions in Alkali Barium Phosphate Glasses

2003 ◽  
Vol 17 (16) ◽  
pp. 3033-3047 ◽  
Author(s):  
V. Ramesh Kumar ◽  
R. P. S. Chakradhar ◽  
A. Murali ◽  
N. O. Gopal ◽  
J. Lakshmana Rao
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Optical Absorption ◽  
Band Gap ◽  
Absorption Spectra ◽  
Optical Band Gap ◽  
Phosphate Glasses ◽  
Epr Spectra ◽  
Optical Absorption Spectra ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic

The electron paramagnetic resonance and optical absorption spectra of VO 2+ ions in different alkali barium phosphate glasses have been studied and the results have been analysed using C4v symmetry. The EPR spectrum shows eight hyperfine lines characteristic of VO 2+ ions. From the observed EPR spectra, the spin-Hamiltonian parameters, Fermi contact interaction parameter k, dipolar hyperfine coupling parameter P have been evaluated. The EPR spectra exhibit a marked concentration dependence. The EPR spectra were also recorded at different temperatures. The number of spins participating in resonance is found to be increasing with decreasing temperature. The paramagnetic susceptibility χ is calculated from the EPR data. As the temperature decreases, χ increases in accordance with Curie's law. The optical absorption spectrum exhibits two bands corresponding to the transitions 2B2g → 2B1g and 2B2g → 2Eg , characteristic of VO 2+ ions in octahedral symmetry with tetragonal distortion. From the ultraviolet edges of these optical absorption spectra, the optical band gap energies (Eopt) of the glass samples have been calculated. The optical band gap energy varies with alkali content. By correlating EPR and optical absorption data, the molecular orbital coefficients have been evaluated. The theoretical values of optical basicity of the glasses have also been evaluated.

Optical band gap in Cd-Mn-phosphate glasses

1995 ◽  
Vol 40 (1) ◽  
pp. 69-72 ◽  
Author(s):  
S.A. Siddiqi ◽  
M. Masih ◽  
A. Mateen
Keyword(s):  
Band Gap ◽  
Optical Band Gap ◽  
Phosphate Glasses

Absorption Properties of Er3+/Nd3+ Co-Doped Magnesium Phosphate Glasses

2017 ◽  
Vol 873 ◽  
pp. 14-19
Author(s):  
Mazlini Mazlan ◽  
Lili Widarti Zainuddin ◽  
Nur Sha’adah Zainuddin ◽  
Md Rahim Sahar
Keyword(s):  
Band Gap ◽  
Optical Band Gap ◽  
Amorphous State ◽  
Band Gap Energy ◽  
Phosphate Glasses ◽  
Magnesium Phosphate ◽  
X Ray Diffraction ◽  
Amorphous Nature ◽  
Thermal Annealing Process ◽  
Co Doped

Magnesium phosphate glasses co-doped with Er3+/Nd3+ concentration were prepared using melt quenching technique and thermal annealing process was proposed to control any defects found in the glass samples. The physical and optical properties of the samples were investigated. The amorphous nature of the samples were confirmed using X-ray diffraction pattern. It shows that all samples are in amorphous state. The optical band gaps and Urbach energies were obtained from the optical absorption spectra. The studyshows that the optical band gap energy,Eopt isincreasingas the Nd2O3 content increased. Meanwhile, Urbach energies, ΔE decreased due to increase of Nd2O3 content. The results obtained from this study shows that the optical band gap, Eopt and the Urbach energy, ΔE are intherange of 3.95 –3.98 eV and 0.367 –0.437 eV respectively.

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