Study on Optical Absorption and Structural Bonding of Lithium Zinc Phosphate Glasses

Abstract

Glasses with chemical composition of (60-x)P2O5-25ZnO-(15+x)Li2O with 0.0 ≤ x ≤ 5.0 mol % are prepared by melt quenching technique. The physical properties, by mean of density and molar volume are determined. The amorphous nature, absorption and structural behaviour are characterized using X-ray Diffraction (XRD), Ultraviolet-visible-near infrared (UV-Vis-NIR) and Fourier transform infrared (FTIR) respectively. In this work, the glass densities are found increases in the range of 2.70 - 2.78 gcm-3 and molar volume decreases from 37.48 - 40.75 gcm-3 with respect to Li2O concentration. Meanwhile, the optical band gap energy for direct and indirect transition are found decreases from 3.074 eV to 2.525 eV and 2.699 eV to 1.670 eV respectively. The Urbach energy is varies as Li2O content increases. The refractive index of these glasses is ranging from 2.48 to 2.90. FTIR spectra exhibited seven bands which centered at 512 cm−1, 767 cm−1, 918 cm−1, 1087 cm−1, 1281 cm−1, 1627 cm−1 and 3441 cm−1 wavenumber that assigned as vibration of Zn-O, symmetric stretching vibration of P-O-P rings, asymmetric stretching vibration of P-O-P groups, asymmetric stretching of PO2-group, asymmetric stretching vibration P=O, bending vibration of water molecule and fundamental stretching of hydroxyl group.

Physical and Structural Properties of Neodymium Doped Lithium Boro-Tellurite Glasses

“…The creation of non-bridging oxygen (NBOs) resulted from the bonds of lithium borate host glass was broken and had increased the free space in the glass network [7]. Then, the density of glass was found increasing from 2.2885 g/cm 3 to 2.4643 g/cm 3 with the increment of Nd2O3 concentration from 0.2 mol% to 0.8 mol% before it started to decrease to 2.4348 g/cm 3 at 1.0 mol%. By increasing Nd2O3, it was found to increase density that attributed to the replacement of lithium ions by neodymium ions, which had higher atomic mass [8].…”

“…A delicate pink tint with violet reflection appears if neodymium oxide is doped to the boro-tellurite based [2]. Furthermore, neodymium is chosen because, it has been recognized as one of the most efficient laser sources for numerous applications in the field of high resolution of spectroscopy [3].…”

Physical, Optical And Radiation Shielding Properties Of Some Phosphate Glasses

“…Then, using the relationship, the molar volume was calculated. ; [11] Vm = M/ρ (2) Where M stands for molecular mass and ρ stands for glass density.…”

“…These optical transitions might be direct or indirect, and they can be permitted or prohibited [16]. The absorption edge in many amorphous materials occurs at elevated energy scope [α >10 4 cm -1 ] obeys "Tauc's law" so the energy gap can be calculated as shown [25]: [11] where B is a constant Eg representing the optical band gap, r is an exponent, which indicates for the direct transition when r= 2 or 3, and for the indirect transition when r=1/2 and r = 3/2 allowed or forbidden, respectively. To differentiate between the various exponents and identify the transition type, we need to identify Eg magnitude.…”

“…The Urbach energy (Ee) values were calculated from Fig.13by taking the reciprocal of the gradients of lined parts of the plots revealed in table3. where Urbach rule for amorphous constituents is specified by[11], α(ν)=Cexp (hν/Ee)[12] where C is constant, and Ee is the Urbach energy. The results which are given in table3, show that the Urbach energy increases with the increased ratio of PbO, other than the energy gap.…”