Optical properties of amorphous Li2O–WO3–B2O3 thin films deposited by electron beam evaporation

Edukondalu, Avula; Rahman, Syed; Ahmmad, Shaik Kareem; Gupta, Ajay; Kumar, K. Siva

doi:10.1016/j.jtusci.2015.03.012

Cited by 21 publications

(6 citation statements)

References 35 publications

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“…The optical absorption coefficient ( α ) as opposed to wavelength (λ) is described as the power portion, which is absorbed per unit length of a medium. The α is assessed from the absorption data investigation using the giving equation [ 6 , 36 , 49 ]

where d and A are the thickness of the samples and the absorbance, respectively; then α can also be defined as a measure of the ability of materials to absorb light photons [ 50 ]. Optical absorption examination offers insight into the solid’s band structure.…”

Section: Resultsmentioning

confidence: 99%

“…Based on the analysis of the α , it is possible to calculate the optical energy band gap (E g ) of the pure PEO as well as PEO/SnTiO 3 NC.To assess the energy gap of the films, Tauc’s relationship can be applied as shown below [ 6 , 50 , 64 ]:

where B isthe constant inside the range of visible frequency and the γ exponent is employed in specifying the electron transitions nature and is reliant on the density of states distribution. γ = 2 or 1/2 to show indirect allowed transition and direct allowed transition, respectively.…”

Section: Resultsmentioning

confidence: 99%

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Optical Dielectric Loss as a Novel Approach to Specify the Types of Electron Transition: XRD and UV-vis as a Non-Destructive Techniques for Structural and Optical Characterization of PEO Based Nanocomposites

et al. 2020

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The structure and optical properties of polyethylene oxide (PEO) doped with tin titanate (SnTiO3) nano-filler were studied by X-ray diffraction (XRD) and UV-Vis spectroscopy as non-destructive techniques. PEO-based composed polymer electrolytes inserted with SnTiO3 nano-particles (NPs) were synthesized through the solution cast technique. The change from crystalline phase to amorphous phase of the host polymer was established by the lowering of the intensity and broadening of the crystalline peaks. The optical constants of PEO/SnTiO3 nano-composite (NC), such as, refractive index (n), optical absorption coefficient (α), dielectric loss (εi), as well as dielectric constant (εr) were determined for pure PEO and PEO/SnTiO3 NC. From these findings, the value of n of PEO altered from 2.13 to 2.47 upon the addition of 4 wt.% SnTiO3NPs. The value of εr also increased from 4.5 to 6.3, with addition of 4 wt.% SnTiO3. The fundamental optical absorption edge of the PEO shifted toward lower photon energy upon the addition of the SnTiO3 NPs, confirming a decrement in the optical band gap energy of PEO. The band gap shifted from 4.78 eV to 4.612 eV for PEO-doped with 4 wt.% SnTiO3. The nature of electronic transitions in the pure and the composite material were studied on the basis of Tauc’s model, while optical εi examination was also carried out to calculate the optical band gap.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Optical Dielectric Loss as a Novel Approach to Specify the Types of Electron Transition: XRD and UV-vis as a Non-Destructive Techniques for Structural and Optical Characterization of PEO Based Nanocomposites

et al. 2020

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“…Regarding amorphous semiconductors with indirect transitions, there is no conservation of electronic momentum when moving from the valence to the conduction band [ 105 ]. The following relationship provides the absorption coefficient for direct band gap materials [ 106 ]:

where hυ stands for photon energy, B is a constant, and E g stands for the OBG energy, while the coefficient n defines the type of electronic transitions that lead to absorption [ 107 ]. Depending on the types of transition, the coefficient n can be 2, 2/3,1/2, or 1/3, corresponding to direct allowed, direct forbidden, indirect allowed, and indirect forbidden transitions, respectively, as shown clearly in Figure 17 [ 96 ].…”

Section: Absorption Coefficient Studymentioning

confidence: 99%

Variation in the Optical Properties of PEO-Based Composites via a Green Metal Complex: Macroscopic Measurements to Explain Microscopic Quantum Transport from the Valence Band to the Conduction Band

Muheddin

Aziz

Mohammed³

2023

Polymers

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In this study, a green chemistry method was used to synthesize polymer composites based on polyethylene oxide (PEO). The method of the remediation of metal complexes used in this study is an environmentally friendly procedure with a low cost. Zinc metal ion (Zn2+)-polyphenol (PPHNL) complexes were synthesized for two minutes via the combination of a black tea leaf (BTL) extract solution with dissolved Zn-acetate. Then, UV–Vis and FTIR were carried out for the Zn-PPHNL complexes in a liquid and solid. The FTIR spectra show that BTLs contain sufficient functional groups (O-H, C-H, C=O, C=C, C-O, C-N, and N-H), PPHNL, and conjugated double bonds to produce metal complexes by capturing the cations of Zn-acetate salt. Moreover, FTIR of the BTL and Zn–PPHNL complexes approves the formation of the Zn-PPHNL complex over the wide variation in the intensity of bands. The UV absorption spectra of BTL and Zn-PPHNL indicate complex formation among tea PPHNL and Zn cations, which enhances the absorption spectra of the Zn-PPHNL to 0.1 compared to the figure of 0.01 associated with the extracted tea solution. According to an XRD analysis, an amorphous Zn-PPHNL complex was created when Zn2+ ions and PPHNL interacted. Additionally, XRD shows that the structure of the PEO composite becomes a more amorphous structure as the concentration of Zn-PPHNL increases. Furthermore, morphological study via an optical microscope (OM) shows that by increasing the concentration of Zn-PPHNL in a PEO polymer composite the size of the spherulites ascribed to the crystalline phase dramatically decreases. The optical properties of PEO: Zn-PPHNL films, via UV–Vis spectroscopy, were rigorously studied. The Eg is calculated by examining the dielectric loss, which is reduced from 5.5 eV to 0.6 eV by increasing the concentration of Zn-PPHNL in the PEO samples. In addition, Tauc’s form was used to specify the category of electronic transitions in the PEO: Zn-PPHNL films. The impact of crystalline structure and morphology on electronic transition types was discussed. Macroscopic measurable parameters, such as the refractive index and extinction coefficient, were used to determine optical dielectric loss. Fundamental optical dielectric functions were used to determine some key parameters. From the viewpoint of quantum transport, electron transitions were discussed. The merit of this work is that microscopic processes related to electron transition from the VB to the CB can be interpreted interms of measurable macroscopic quantities.

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“…where, "hν" represents photon energy, "B" is a constant, and the coefficient "m" decides the type of electronic transitions that result in absorption. 31 Figure 4 clearly illustrates that the coefficient "m" can take on different values (2, 2/3, 1/2, or 1/3) depending on the type of transition, namely direct allowed, direct forbidden, indirect allowed, or indirect forbidden transitions. 32 By analyzing the linear sections of (αhν) m in Figure 5a-d and where they intercept the photon energy axis (hν), it is possible to determine the value of E g .…”

Section: Tauc's Model For Band Gap Studymentioning

confidence: 99%

Studying the optoelectronic properties and emission quenching dynamics of poly‐TPD by incorporating ZnO nanoparticles and multiwalled carbon nanotubes

Al‐Asbahi

2023

J of Applied Polymer Sci

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In this study, the optoelectronic properties and emission dynamic quenching of poly‐TPD were investigated upon incorporating ZnO nanoparticles and multiwalled carbon nanotubes (MWCNTs). A solution blending method was utilized to successfully prepare poly‐TPD incorporated with various contents of ZnO/MWCNT nanocomposites. The optoelectronic properties of the nanocomposites were analyzed using UV–Vis and photoluminescence spectrophotometry. The incorporation of the nanocomposites resulted in a decrease in transmittance, reflectance, and absorption edge, indicating a reduction in the poly‐TPD's bandgap. Parameters such as extinction coefficient, Urbach energy, and charge carrier density also decreased with addition of the nanocomposites, suggesting increased scattering, disorder, and the presence of defect states. The decrease in bandgap from 2.970 to 2.852 eV with increasing the nanocomposite content confirmed the emergence of new electronic states. Furthermore, the nature of the transitions changed from direct allowed for pure poly‐TPD to direct forbidden upon incorporation of the nanocomposites. The inclusion of the nanocomposites also led to a decrease in refractive index and fluorescence intensity. The observed fluorescence quenching primarily exhibited dynamic characteristics, with a Stern–Volmer constant of 5.14 L/g and quenching rate constants surpassing the minimum threshold for efficient quenching. The increase in charge transfer rate constants with the nanocomposite content indicated enhanced quenching efficiency and charge transfer, likely due to the increased surface area and presence of defects. These findings suggest that poly‐TPD incorporated with ZnO/MWCNT nanocomposites displays promising properties for applications in optoelectronic devices.

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Optical properties of amorphous Li₂O–WO₃–B₂O₃ thin films deposited by electron beam evaporation

Abstract: (2016) Optical properties of amorphous Li 2 O-WO 3-B 2 O 3 thin films deposited by electron beam evaporation,

Cited by 21 publications

References 35 publications

Optical Dielectric Loss as a Novel Approach to Specify the Types of Electron Transition: XRD and UV-vis as a Non-Destructive Techniques for Structural and Optical Characterization of PEO Based Nanocomposites

Optical Dielectric Loss as a Novel Approach to Specify the Types of Electron Transition: XRD and UV-vis as a Non-Destructive Techniques for Structural and Optical Characterization of PEO Based Nanocomposites

Variation in the Optical Properties of PEO-Based Composites via a Green Metal Complex: Macroscopic Measurements to Explain Microscopic Quantum Transport from the Valence Band to the Conduction Band

Studying the optoelectronic properties and emission quenching dynamics of poly‐TPD by incorporating ZnO nanoparticles and multiwalled carbon nanotubes

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