Effect of Hydrogen Coverage on Elastic and Optical Properties of Silicene: A First-Principle Study

2021 ◽  
Author(s):  
Santosh Routu ◽  
Jagan Mohana Rao Malla ◽  
Suresh Yathirajula ◽  
Nageswar rao Uppala
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
First Principles ◽  
Visible Range ◽  
Optical Parameters ◽  
First Principle ◽  
Plasmon Energy ◽  
Estimated Parameters ◽  
First Time ◽  
Constant Refractive Index

Abstract The structural, electronic, and optical properties of hydrogenated silicene have been investigated using first-principles DFT calculations. In comparison to pristine silicene, the hydrogenated silicene exhibits high stability, reduced anisotropy, and less birefringence. In the visible range, hydrogenated silicene exhibits a constant refractive index than silicene. The elastic and optical parameters: Young’s modulus (Y), poisson’s ratio (ν), bulk modulus (B), shear modulus (G), dielectric constant ε(0), refractive index n(0), conductivity threshold (Eth), birefringence Δn(0), and plasmon energy (ħωp) were calculated for the first time for various hydrogen occupancy levels. The estimated parameters are agree well with the experimental and reported values that are available.

scholarly journals First-Principles Study of ZnIn2Te4 and HgIn2Te4 Defect-Chalcopyrite Semiconductors Under Different Pressures: Electronic, Elastic, And Optical Properties

2021 ◽  
Author(s):  
SATISH CHANDRA ◽  
V. Kumar
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Reasonable Agreement ◽  
Local Density ◽  
Optical Parameters ◽  
First Principle ◽  
Elastic Parameters ◽  
First Principle Calculations ◽  
Chalcopyrite Semiconductors ◽  
First Time

Abstract First-principle calculations of electronic, elastic, and optical properties for ZnIn2Te4 and HgIn2Te4 defect-chalcopyrite semiconductors have been performed using local density approximation (LDA). Computed energy bandgaps are 1.398 eV and 1.101 eV, respectively, for ZnIn2Te4 and HgIn2Te4, which show the indirect bandgaps behavior. Elastic parameters and Debye temperature have also been investigated at 0, 5, 10, 13, and 14 GPa pressures. Calculated results indicate that both semiconductors are covalent in nature at 0 GPa and become ionic afterward. Optical parameters have also been examined under 0, 5, 10, and 13 GPa in the energy span of 0 eV to 15 eV. The calculated values indicate that these semiconductors are mechanically stable up to 13 GPa and become unstable at 14 GPa. The Calculated values of all parameters are compared with the available experimental and reported values at 0 GPa. A reasonable agreement has been obtained between them. The values of these parameters at 5, 10, 13, and 14 GPa pressures are reported for the first time.

The Stability, Structural, Electronic, and Optical Properties of Hydrogenated Silicene Under Hydrostatic Pressures: A First-principle Study

2021 ◽  
Author(s):  
V Kumar ◽  
R Santosh
Keyword(s):  
Optical Properties ◽  
Binding Energy ◽  
Optical Parameters ◽  
First Principle ◽  
Plasmon Energy ◽  
Electronic And Optical Properties ◽  
First Principle Calculations ◽  
The Stability ◽  
First Time ◽  
Good Agreement

Abstract The structural, electronic, and optical properties of hydrogenated silicene have been studied under different hydrostatic pressures using first-principle calculations. The binding energy and band structure have been calculated for Chair (C-) and Boat (B-) structures, which are having good stability at 0 GPa, 3 GPa, 6 GPa, 9 GPa, 12 GPa, 15 GPa, and 18 GPa hydrostatic pressures. Stability has been verified using binding energy and phonon calculations. The C- and B- structures have become metallic and unstable at 21 GPa. The optical properties of B-configuration have been studied in the energy range of 0-20 eV. Five optical parameters such as conductivity threshold (σth), dielectric constant ε(0), refractive index n(0), birefringence Δn(0) and plasmon energy (ħωp) have been calculated for the first time under different hydrostatic pressures. The calculated values are in good agreement with the reported values at 0 GPa.

First principle investigations of the Pbnm phase BiFeO3, BiFe0.875Mn0.125O3 and Bi0.875X0.125Fe0.875Mn0.125O3 (XBFM) (X = Ce, Gd, Lu)

2017 ◽  
Vol 31 (32) ◽  
pp. 1750304 ◽  
Author(s):  
Ren Zhang ◽  
Yunhua Zhou ◽  
Yiyi Zhu ◽  
Yangyang Li ◽  
Liang Chu ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Absorption Spectrum ◽  
Loss Function ◽  
Magnetic Moment ◽  
First Principles ◽  
Magnetic Moments ◽  
First Principle ◽  
Reflectivity Spectrum ◽  
Densities Of States

The structural, magnetic, electronic and optical properties of Pbnm BiFeO[Formula: see text] (BFO), BiFe[Formula: see text]Mn[Formula: see text]O[Formula: see text] (BFM), Bi[Formula: see text]X[Formula: see text]Fe[Formula: see text]Mn[Formula: see text]O[Formula: see text] (XBFM) (X = Ce, Gd, Lu) have been investigated by the first principles within the PBE[Formula: see text]+[Formula: see text]U scheme. It is shown that the dopant Mn in the B sites and Ce (Gd, Lu) in the A sites improves the crystalline quality. The magnetic moments of Bi[Formula: see text]Ce[Formula: see text]Fe[Formula: see text]Mn[Formula: see text]O[Formula: see text] (CBFM) and Bi[Formula: see text]Gd[Formula: see text]Fe[Formula: see text]Mn[Formula: see text]O[Formula: see text] (GBFM) are 10 [Formula: see text] and 16 [Formula: see text] which mainly arises from the strongly localized unpaired 4f electrons of Ce and Gd, 3d electrons of Mn and Fe. While, as BFM, the magnetic moment of Bi[Formula: see text]Lu[Formula: see text]Fe[Formula: see text]Mn[Formula: see text]O[Formula: see text] (LBFM) is 9 [Formula: see text] indicating no effect on the magnetization is made by Lu for its full 4f states. The densities of states of the five systems hint that CBFM is metallic and BFM, GBFM, LBFM are still semiconductors. The metallic properties of CBFM arise from the hybridization between Ce-4f and Mn-3d states which leads the Mn [Formula: see text] states to be split into [Formula: see text] and [Formula: see text] lowering the bottom of the conduction band to cross the Fermi level. Furthermore, we also study the optical properties of Pbnm BiFeO[Formula: see text] (BFO), BiFe[Formula: see text]Mn[Formula: see text]O[Formula: see text] (BFM), Bi[Formula: see text]X[Formula: see text]Fe[Formula: see text]Mn[Formula: see text]O[Formula: see text] (XBFM) (X = Ce, Gd, Lu). In this work, the optical properties including the absorption spectrum, loss function, refractive index and reflectivity spectrum are discussed in detail.

scholarly journals Sulvanite Compounds Cu3TMS4 (TM = V, Nb and Ta): Elastic, Electronic, Optical and Thermal Properties using First-principles Method

2014 ◽  
Vol 6 (3) ◽  
pp. 407-419 ◽  
Author(s):  
M. A. Ali ◽  
N. Jahan ◽  
A. K. M. A. Islam
Keyword(s):  
Refractive Index ◽  
First Principles ◽  
Theoretical Data ◽  
Debye Model ◽  
Measured Data ◽  
Band Gaps ◽  
Visible Range ◽  
Energy Dependent ◽  
First Time ◽  
Calculation Code

We present a systematic first-principles study of the structural, elastic, electronic, optical and thermodynamics properties of the sulvanite compounds Cu3TMS4 (TM = V, Nb and Ta). The structural, elastic and electronic properties are in fact revisited using a different calculation code than that used by other workers and the results are compared. The band gaps are found to be 1.041, 1.667 and 1.815 eV for Cu3VS4, Cu3NbS4 and Cu3TaS4, respectively which are comparable to other available calculated results. The optical properties such as dielectric function, refractive index, photoconductivity, absorption coefficients, reflectivity and loss function have been calculated for the first time. The calculated results are compared with the limited measured data on energy dependent refractive index and reflectivity coefficient available only for Cu3TaS4. All the materials are dielectric, transparent in the visible range. The values of plasma frequencies are found to be 15.36, 15.58 and 15.64 eV for Cu3VS4, Cu3NbS4 and Cu3TaS4, respectively. Furthermore, following the quasi-harmonic Debye model, the temperature effect on the bulk modulus, heat capacity, and Debye temperature is calculated reflecting the anharmonic phonon effects and these are compared with both experimental and other theoretical data where available. © 2014 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi: http://dx.doi.org/10.3329/jsr.v6i3.19191 J. Sci. Res. 6 (3), 407-419 (2014)

scholarly journals The effect of pressure on structural, stability, electronic, and optical properties of hydrogenated silicene: A first-principle study

2021 ◽  
Author(s):  
V Kumar ◽  
R. Santosh
Keyword(s):  
Optical Properties ◽  
Binding Energy ◽  
External Pressure ◽  
Optical Parameters ◽  
First Principle ◽  
Electronic And Optical Properties ◽  
External Pressures ◽  
The Stability ◽  
First Time ◽  
Good Agreement

Abstract The structural, electronic, and optical properties of hydrogenated silicene have been studied under different pressures using first-principle calculations. The binding energy and band structure have been calculated for two stable structures: Chair (C-) and Boat (B-) in the range of 0–21 GPa external pressure. The behavior of stability and energy bandgap have been analyzed under different external pressures. The stability has been verified using binding energy and phonon data. The C- and B- structures have zero bandgaps at 21 GPa and become unstable. The optical properties of B-configuration have been studied in the energy range of 0–20 eV. Five optical parameters such as conductivity threshold (σth), dielectric constant ε(0), refractive index n(0), birefringence Δn(0) and plasmon energy (ħωp) have been calculated for the first time under different pressures. The calculated values are in good agreement with the reported values at 0 GPa.

The Structural, Electronic and Optical Properties of Hydrofluorinated Germanene (GeH1-xFx): A First-Principles Study

2021 ◽  
Author(s):  
V Kumar ◽  
R Santosh ◽  
Anita Sinha ◽  
J Kumar
Keyword(s):  
Heat Capacity ◽  
Optical Properties ◽  
Binding Energy ◽  
First Principles ◽  
Structural Parameters ◽  
Plasmon Energy ◽  
Electronic And Optical Properties ◽  
Energy Bandgap ◽  
The Stability ◽  
First Time

Abstract The structural, electronic, and optical properties of hydrofluorinated germanene have been studied with different occupancy ratios of fluorine and hydrogen. The hybridization of H-1s and Ge-4p orbitals in hydrogenated germanene and F-2p and Ge-4p orbitals in fluorinated germanene plays a significant role in creating an energy bandgap. The binding energy and phonon calculations confirm the stability of hydrofluorinated germanene decreases with the increase of the F to H ratio. The value of the energy bandgap decreased by increasing the ratio of F and H. The optical properties have been studied in the energy range of 0-25 eV. Six essential parameters such as energy bandgap (Eg), binding energy (Eb), dielectric constant ε(0), refractive index n(0), plasmon energy (ћωp), and heat capacity (Cp) have been calculated for different occupancies of H and F in hydrofluorinated germanene for the first time. The calculated values of structural parameters agree well with the available experimental and reported values.

scholarly journals Synthesis of PVA/CeO2 Based Nanocomposites with Tuned Refractive Index and Reduced Absorption Edge: Structural and Optical Studies

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1570
Author(s):  
Shujahadeen B. Aziz ◽  
Elham M. A. Dannoun ◽  
Dana A. Tahir ◽  
Sarkawt A. Hussen ◽  
Rebar T. Abdulwahid ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Absorption Edge ◽  
Ceo2 Nanoparticles ◽  
Poly Vinyl Alcohol ◽  
Optical Parameters ◽  
Single Oscillator Model ◽  
Vis Spectroscopy ◽  
The Impact ◽  
Host Polymer

In the current study, polymer nanocomposites (NCPs) based on poly (vinyl alcohol) (PVA) with altered refractive index and absorption edge were synthesized by means of a solution cast technique. The characterization techniques of UV–Vis spectroscopy and XRD were used to inspect the structural and optical properties of the prepared films. The XRD patterns of the doped samples have shown clear amendments in the structural properties of the PVA host polymer. Various optical parameters were studied to get more insights about the influence of CeO2 on optical properties of PVA. On the insertion of CeO2 nanoparticles (NPs) into the PVA matrix, the absorption edge was found to move to reduced photon energy sides. It was concluded that the CeO2 nanoparticles can be used to tune the refractive index (n) of the host polymer, and it reached up to 1.93 for 7 wt.% of CeO2 content. A detailed study of the bandgap (BG) was conducted using two approaches. The outcomes have confirmed the impact of the nanofiller on the BG reduction of the host polymer. The results of the optical BG study highlighted that it is crucial to address the ɛ” parameter during the BG analysis, and it is considered as a useful tool to specify the type of electronic transitions. Finally, the dispersion region of n is conferred in terms of the Wemple–DiDomenico single oscillator model.

scholarly journals Polymer Composites with 0.98 Transparencies and Small Optical Energy Band Gap Using a Promising Green Methodology: Structural and Optical Properties

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1648
Author(s):  
Muaffaq M. Nofal ◽  
Shujahadeen B. Aziz ◽  
Jihad M. Hadi ◽  
Wrya O. Karim ◽  
Elham M. A. Dannoun ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Polymer Composites ◽  
Amorphous Phase ◽  
Absorption Edge ◽  
Complex Form ◽  
Bandgap Energy ◽  
Optical Parameters ◽  
Visible Spectroscopy ◽  
Uv Visible

In this work, a green approach was implemented to prepare polymer composites using polyvinyl alcohol polymer and the extract of black tea leaves (polyphenols) in a complex form with Co2+ ions. A range of techniques was used to characterize the Co2+ complex and polymer composite, such as Ultraviolet–visible (UV-Visible) spectroscopy, Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The optical parameters of absorption edge, refractive index (n), dielectric properties including real and imaginary parts (εr, and εi) were also investigated. The FRIR and XRD spectra were used to examine the compatibility between the PVA polymer and Co2+-polyphenol complex. The extent of interaction was evidenced from the shifts and change in the intensity of the peaks. The relatively wide amorphous phase in PVA polymer increased upon insertion of the Co2+-polyphenol complex. The amorphous character of the Co2+ complex was emphasized with the appearance of a hump in the XRD pattern. From UV-Visible spectroscopy, the optical properties, such as absorption edge, refractive index (n), (εr), (εi), and bandgap energy (Eg) of parent PVA and composite films were specified. The Eg of PVA was lowered from 5.8 to 1.82 eV upon addition of 45 mL of Co2+-polyphenol complex. The N/m* was calculated from the optical dielectric function. Ultimately, various types of electronic transitions within the polymer composites were specified using Tauc’s method. The direct bandgap (DBG) treatment of polymer composites with a developed amorphous phase is fundamental for commercialization in optoelectronic devices.

scholarly journals Flexible Methyl Cellulose/Polyaniline/Silver Composite Films with Enhanced Linear and Nonlinear Optical Properties

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1225
Author(s):  
Ali Atta ◽  
Mostufa M. Abdelhamied ◽  
Ahmed M. Abdelreheem ◽  
Mohamed R. Berber
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Band Gap ◽  
Nonlinear Optical ◽  
Composite Films ◽  
Methyl Cellulose ◽  
Carbon Cluster ◽  
Nonlinear Susceptibility ◽  
Optical Parameters ◽  
Flexible Polymer

In order to potentiate implementations in optical energy applications, flexible polymer composite films comprising methyl cellulose (MC), polyaniline (PANI) and silver nanoparticles (AgNPs) were successfully fabricated through a cast preparation method. The composite structure of the fabricated film was confirmed by X-ray diffraction and infrared spectroscopy, indicating a successful incorporation of AgNPs into the MC/PANI blend. The scanning electron microscope (SEM) images have indicated a homogenous loading and dispersion of AgNPs into the MC/PANI blend. The optical parameters such as band gap (Eg), absorption edge (Ed), number of carbon cluster (N) and Urbach energy (Eu) of pure MC polymer, MC/PANI blend and MC/PANI/Ag films were determined using the UV optical absorbance. The effects of AgNPs and PANI on MC polymer linear optical (LO) and nonlinear optical (NLO) parameters including reflection extinction coefficient, refractive index, dielectric constant, nonlinear refractive index, and nonlinear susceptibility are studied. The results showed a decrease in the band gap of MC/PANI/AgNPs compared to the pure MC film. Meanwhile, the estimated carbon cluster number enhanced with the incorporation of the AgNPs. The inclusion of AgNPs and PANI has enhanced the optical properties of the MC polymer, providing a new composite suitable for energy conversion systems, solar cells, biosensors, and nonlinear optical applications.

Effect of non-annealed and annealed ZnO on the optical properties of PVC/ZnO nanocomposite films

2021 ◽  
pp. 089270572110386
Author(s):  
Ali F Al-Shawabkeh ◽  
Ziad M Elimat ◽  
Khaleel N Abushgair
Keyword(s):  
Dielectric Constant ◽  
Refractive Index ◽  
Optical Properties ◽  
Zno Nanoparticles ◽  
Oscillator Strengths ◽  
Nanocomposite Films ◽  
Optical Parameters ◽  
Zno Nanoparticle ◽  
Dispersion Energy ◽  
Optical Susceptibility

The goal of this study was to investigate the optical properties of the prepared polyvinyl chloride (PVC)/zinc oxide (ZnO) nanocomposite films. The PVC/ZnO nanocomposite films consist of the addition of different concentrations with both non-annealed ZnO nanoparticles and ZnO nanoparticles annealed at temperature of 700°C. The PVC/ZnO nanocomposite films by weight concentrations of (0 wt.%, 2.5 wt.%, 5 wt.% and 10 wt.%) have been prepared by the casting method. The optical absorbance and transmittance values of the composites films were measured in the wavelength range between (250 to 1100 nm) at room temperature by using the UV-1800 Shimadzu spectrophotometer. The optical properties (absorption coefficient, dielectric constant, refractive index, and optical conductivity) have been investigated by the ultraviolet (UV) spectrophotometer. The optical parameters (direct optical energy gap, excitation energy for electronic transitions, the dispersion energy, static refractive index, static dielectric constant, optical oscillator strengths, the moments of optical spectrum, linear optical susceptibility, third-order nonlinear optical susceptibility, nonlinear refractive index, high-frequency dielectric constant, the carrier concentration to the effective mass ratio, the long wavelength refractive index and the plasma frequency) were calculated. The results showed that the optical properties behavior of the PVC/ZnO nanocomposite films was found to be dependent on the ZnO concentration, and photon wavelength. In addition, the results of the study show that the optical parameters can be influenced by alter the concentration of the nonannealed and annealed a ZnO nanoparticle in the PVC polymer matrix.

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