Abstract:Glass composition (30 − x) SrO-xAl 2 O 3-69.5B 2 O 3-0.5CuO (0 ≤ x ≤ 15 mol%) captioned as SABC was prepared by the conventional melt quenching technique. Peak-free X-ray diffractograms and homogeneous plain SEM image confirm the glassy nature of the prepared samples. EPR and optical absorption spectral studies were carried out to understand the effect of modifier oxide (SrO) and transition metal (TM) ion Cu 2+ in the glass network. From the EPR spectra, spin-Hamiltonian parameters were evaluated. It was obser… Show more
“…The boroxol ring breathing of the considered borate network appeared at 803 cm −1 47 , 51 , 52 . The pyroborate vibrations and ortho-borate groups arose at 842 and 882 cm −1 respectively 50 , 53 . Figure 3 ( a ) Raman spectra of the considered ErCoCu1-6 glasses and ( b ) The deconvoluted spectra (host glass ErCoCu1 as an example).…”
A host glass network of 70B2O3–10Pb3O4–18ZnO–2Er2O3 (ErCoCu1) was proposed and the impact of 1 mol% of Co or/and Cu ions on its structural, thermal, optical, and green emission properties was studied extensively. The X-ray diffraction spectra confirmed the amorphous structure of the produced glasses. Density and density-based parameters behavior showed that the Co or/and Cu ions fill the interstitial positions of the proposed ErCoCu1 network, causing its compactness. Both ATR-FTIR and Raman Spectra affirmed the formation of the fundamental structural units of the borate network, B–O–B linkage, BO3, and BO4. Additionally, the penetration of Co or/and Cu ions inside the ErCoCu1 converts the tetrahedral BO4 units to triangle BO3 causing its richness by non-bridging oxygens. The addition of Co or/and Cu reduces the glass transition temperature as a result of the conversion of the BO4 to BO3 units. Optical absorption spectra for the host glass ErCoCu1 showed many of the distinguished absorption bands of the Er3+ ion. Penetration of Co ion generates two broadbands referring to the presence of Co2+ ions in both tetrahedral and octahedral coordination and Co3+ ions in the tetrahedral coordination. In the Cu-doped glasses, the characteristic absorption bands of Cu2+ and Cu+ were observed. A green emission was generated from the ErCoCu1 glass under 380 nm excitation wavelength. Moreover, no significant effect of Co or/and Cu on the emission spectra was recorded. The considered glasses had appropriate properties qualifying them for optoelectronics and nonlinear optics applications.
“…The boroxol ring breathing of the considered borate network appeared at 803 cm −1 47 , 51 , 52 . The pyroborate vibrations and ortho-borate groups arose at 842 and 882 cm −1 respectively 50 , 53 . Figure 3 ( a ) Raman spectra of the considered ErCoCu1-6 glasses and ( b ) The deconvoluted spectra (host glass ErCoCu1 as an example).…”
A host glass network of 70B2O3–10Pb3O4–18ZnO–2Er2O3 (ErCoCu1) was proposed and the impact of 1 mol% of Co or/and Cu ions on its structural, thermal, optical, and green emission properties was studied extensively. The X-ray diffraction spectra confirmed the amorphous structure of the produced glasses. Density and density-based parameters behavior showed that the Co or/and Cu ions fill the interstitial positions of the proposed ErCoCu1 network, causing its compactness. Both ATR-FTIR and Raman Spectra affirmed the formation of the fundamental structural units of the borate network, B–O–B linkage, BO3, and BO4. Additionally, the penetration of Co or/and Cu ions inside the ErCoCu1 converts the tetrahedral BO4 units to triangle BO3 causing its richness by non-bridging oxygens. The addition of Co or/and Cu reduces the glass transition temperature as a result of the conversion of the BO4 to BO3 units. Optical absorption spectra for the host glass ErCoCu1 showed many of the distinguished absorption bands of the Er3+ ion. Penetration of Co ion generates two broadbands referring to the presence of Co2+ ions in both tetrahedral and octahedral coordination and Co3+ ions in the tetrahedral coordination. In the Cu-doped glasses, the characteristic absorption bands of Cu2+ and Cu+ were observed. A green emission was generated from the ErCoCu1 glass under 380 nm excitation wavelength. Moreover, no significant effect of Co or/and Cu on the emission spectra was recorded. The considered glasses had appropriate properties qualifying them for optoelectronics and nonlinear optics applications.
“…Wang et al [35] observed blue shift for nanoparticles and nanorod, which is due to quantum confinement effect. Calculation of optical energy gap of compounds from the absorbance spectra using Woods and Tauc's function [36] is given as where α is the linear absorption co-efficient of the materials, hν is the energy of the photon, 'A' is proportionality constant of characteristic material, and n equals either ½ for indirect transition or 2 for direct transitions (Fig. 10) [37] .…”
The effects of Yb, Er on structural, optical, magnetic and biocompatibility of β-NaYF 4 compounds were examined. The pure and Yb, Er-doped β-NaYF 4 compounds were synthesized via simple hydrothermal method. X-ray diffraction analysis revealed the hexagonal crystal structure. The functional group present in the sample was identified by FT-IR analysis. The vibrational bands were analysed by Raman spectroscopy. Electron Microscope images exhibit the hexagonal plate-like morphology. The characteristic absorbance peaks of Yb, Er and host were obtained in UV-VIS-NIR absorbance spectra. The interesting green and enhanced red emission through Photoluminescence spectra of the prepared compounds might be useful for bio-imaging. Pure β-NaYF 4 possessed diamagnetic property and Yb, Er-doped β-NaYF 4 exhibited paramagnetic property at room temperature. Yb, Er-doped β-NaYF 4 was incubated with HeLa cells and assessed cytotoxicity using MTT assay. Hence, Yb, Er-doped β-NaYF 4 materials have promising application in cell imaging and bio-separation applications.
“…As it is known, one can adopt the electron paramagnetic resonance (EPR) technique to conveniently study the structures of the glasses by using probing agents such as the transition metal ions (e.g. W 5+ [8,[11][12][13], Mo 5+ [14][15][16], VO 2+ [17][18][19][20], Cu 2+ [17,[21][22][23], Cr 5+ [24][25][26]). EPR experiments for the glasses system P 2 O 5 -Li 2 WO 4 -Li 2 O were carried out decades ago [15] and the EPR parameters g-factors (g and g ⊥ ) of the W 5+ ions reduced from W 6+ in the formation of the glasses system P 2 O 5 -Li 2 WO 4 -Li 2 O were obtained in the experiment [15].…”
In this work, we adopt the three-order perturbation formulae for g-factors (g//, g^) of d1 ions in the octahedral environment to calculate the g-factors of W5+ ions in tungsten phosphate glasses containing lithium (P2O5-Li2WO4-Li2O). In the light of the high valence state of the studied W5+ centers and hence the strong covalency of the studied octahedral [WO6]7- cluster, we consider the contributions to g-factors from the ligand orbital and spin-orbit (SO) coupling interactions based on the cluster approach. The required tetragonal crystal-field parameters are calculated from the local structure of W5+ ions based on the superposition model. According to the theoretical calculations, we find that the octahedral [WO6]7- clusters possess the tetragonally compressed distortion with a shorter W-O bond length (≈1.54 Å) and a longer one (≈2.26 Å) along C4 axis and four normal W-O bond length (≈1.94 Å) in the perpendicular plane, which infers that the W5+ ions are in the form of tungstyl ions (i.e., WO3-). Based on the local structural data, the theoretical values of g// and g^ agree well with the experimental values.
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