scholarly journals A DFT study of the effects of Sc doping on electronic and optical properties of CdS nanoparticles

2015 ◽  
Vol 33 (4) ◽  
pp. 782-791
Author(s):  
Shafiq Ur Rehman ◽  
Abdul Majid ◽  
Najmal Hassan ◽  
Abdul Shakoor ◽  
G. Murtaza ◽  
...  
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Geometry Optimization ◽  
Blue Shift ◽  
Dft Method ◽  
Integration Scheme ◽  
Cds Nanoparticles ◽  
Electronic And Optical Properties ◽  
Numerical Integration Scheme ◽  
Homo Lumo

AbstractIn the present work a systematic study was carried out to understand the influence of Sc doping on electronic and optical properties of CdS nanoparticles. The geometry optimization and symmetry computation for CdS and Sc doped CdS nanoparticles using Density Functional Theory (DFT) on B3LYP level with the QZ4P for Cd and DZ2P for sulphur and Sc were performed by Amsterdam Density Functional (ADF). The results show that HOMO-LUMO gap as well as electronic and optical properties of CdS clusters vary with Sc doping. The HOMO-LUMO gap is affected by the dopant and its value decreases to 0.6 eV. Through considering the numerical integration scheme in the ADF package, we investigated different vibrational modes and our calculated Raman and IR spectra are consistent with the reported result. The calculated IR and Raman peaks of CdS and Sc doped CdS clusters were in the range of 100 to 289 cm−1, 60 cm−1 to 350 cm−1 and 99 cm−1 to 282 cm−1, 60 cm−1 to 350 cm−1, respectively, which was also confirmed by experiment as well as a blue shift occurrence. Subsequently, for deeper research of pure and doped CdS clusters, their absorption spectra were calculated using time-dependent DFT method.

scholarly journals First-Principles Studies on Structural, Electronic and Optical Properties of Fe-doped Nis2 Counter Electrode for Dye-Sensitized Solar Cells using Dft+U

2020 ◽  
Vol 17 (2) ◽  
pp. 81
Author(s):  
Nur Aisyah Ab Malik Marwan ◽  
Nurakma Natasya Md Jahangir Alam ◽  
Mohd Hazrie Samat ◽  
Muhammad Zamir Mohyedin ◽  
Nur Hafiz Hussin ◽  
...  
Keyword(s):  
Optical Properties ◽  
Solar Cells ◽  
First Principles ◽  
Density Functional ◽  
Counter Electrode ◽  
Dye Sensitized Solar Cells ◽  
Dft Method ◽  
Electronic And Optical Properties ◽  
Dye Sensitized ◽  
Sensitized Solar Cells

The structural, electronic and optical properties of nickel disulfide (NiS2) and iron (Fe)-doped NiS2 were computed by using first-principles calculations through the density functional theory (DFT) method. The Fe was used as a dopant element to understand the behavior and the key mechanism of Fe-doped NiS2 as a counter electrode in dye-sensitized solar cells (DSSC). The results indicated that the structural properties of the NiS2 as the cubic crystal structure with the space group Pa3 (205) (pyrite structure type) agree with experimental data. The density of states (DOS) of NiS2 and Fe-doped NiS2 shows a gapless bandgap due to Mott insulator behavior. As for optical properties, the optical absorption of NiS2 is shifted towards the infrared (IR) region when doping with Fe while the conductivity of Fe-doped NiS2 is slightly higher in conductivity. These optical properties show that Fe-doped NiS2 is good for photocatalytic activity and may provide an excellent electron charge transfer for a counter electrode in DSSC

scholarly journals Effect of Ru, Rh, Mo, and Pd Adsorption on the Electronic and Optical Properties of Anatase TiO2(101): A DFT Investigation

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 814 ◽  
Author(s):  
Peng Gao ◽  
Libin Yang ◽  
Songtao Xiao ◽  
Lingyu Wang ◽  
Wei Guo ◽  
...  
Keyword(s):  
Optical Properties ◽  
Photocatalytic Activity ◽  
Metal Atom ◽  
Density Functional ◽  
Hydrogen Generation ◽  
Dft Method ◽  
Anatase Tio2 ◽  
Electronic And Optical Properties ◽  
Defect Site ◽  
Metal Atoms

Adsorbed metal atoms and metal doping onto TiO2 can effectively enhance the optical and photocatalytic activity of photocatalytic efficiency of titanium dioxide (TiO2), favoring the extension of its optical absorption spectrum and the efficiency of hydrogen generation. To investigate the possible mechanism causing potential improvement of photocatalytic activity, the electronic and optical properties of the anatase TiO2(101) plane with different adsorbed metal atom have been theoretically calculated through density functional theory (DFT) method. Adsorption of Pd and Ru atoms increases the delocalization of the density of states, with an impurity state near the Fermi level. Moreover, the investigated adsorbed metal atoms (Mo, Pd, Ru, Rh) narrow the band gap of anatase TiO2, thus enhancing the probability of photoactivation by visible light. The orbital hybridization of the d orbit from the adsorbed metal atom and the p orbit from the O of the defect site increases the Schottky barrier of the electronic structure.

Structural, Electronic and Optical Properties of SiC Quantum Dots

2012 ◽  
Vol 18-19 ◽  
pp. 77-87 ◽  
Author(s):  
Jian Guang Wang ◽  
Peter Kroll
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Density Functional ◽  
Tensile Strain ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
Energy Gaps ◽  
Quantum Confinement Effects ◽  
Homo Lumo

We Perform Density Functional Theory Calculations of the Hydrogen-Passivated Topological Silicon Carbide Quantum Dots (QDs) and Investigate their Structural, Electronic and Optical Properties. We Study Clusters Constructed from 3C-Sic with up to 8 Topological Shells, Corresponding to Diameters up to 2.2 Nm, Terminated Homogeneously with either Si-H or C-H Bonds. All Qds Exhibit Tensile Strain (1-5 %) within the Cluster Core. the Larger the Cluster, the Smaller the Strain in the Interior, however. Tensile Strain Increases from the inside of the Cluster towards the outside, Reaches a Maximum at the Second Layer below the Surface, and Vanishes only for Bonds Involving Surface Si or C Atoms. Quantum-Confinement Effects Are Observed for the Energy Gaps and Optical Gaps of SiC QDs. Size Has a Major Impact on the Absorption Edge in Comparison to a Weak Effect on the Photon Energy of the Spectra Maxima. Our Calculations Show that Surface Termination Plays a Crucial Role and Strongly Affects Energy Gaps, Optical Gaps and Optical Spectra. Orbitals around the HOMO-LUMO Gap Predominantly Localize within the Core of the Cluster, with Significant Contributions by the Surface for Si-H Terminated Clusters only.

scholarly journals Theoretical Studies on the Structural, Electronic and Optical Properties of the New π-conjugated Copolymers Based on Carbazole and Thiophene

2011 ◽  
Vol 4 (1) ◽  
pp. 119 ◽  
Author(s):  
Z. El Maliki ◽  
M. Bouachrine ◽  
M. Hamidi ◽  
L. Bejjit ◽  
M. Haddad
Keyword(s):  
Optical Properties ◽  
Molecular Geometry ◽  
Dft Method ◽  
Optoelectronic Properties ◽  
Polymer Materials ◽  
Organic Polymer ◽  
Excitation Energies ◽  
Electronic And Optical Properties ◽  
Td Dft ◽  
Homo Lumo

This work reports a theoretical investigation of π-conjugated oligomers constituted by n units (n = 1-4) based on carbazole and ethylenedioxythiophene. The molecular geometry, torsional potential, electronic and optical properties of the oligomers [Cbz-(Edot)n-Cbz] (n = 1-4) are investigated using DFT (B3LYP/3-21G*) calculations. The discussion is focused on the influence of chain length on the properties of these copolymers. The analyses of torsional angles for [Cbz-(Edot)4-Cbz] reveal that the structure has a anti-planar conformation. The electronic properties of the molecules, HOMO, LUMO and Eg (HOMO-LUMO), are studied using B3LYP functional. The results have been compared with those of thiophene and ethylenedioxythiophene. The lowest excitation energies (Eex) and the maximal absorption wavelength (λabs) are studied using the TD/DFT, ZINDO and CIS methods. The electronic transitions of the absorption spectrum derived by TD/DFT method give useful structural and electronic information for designing novel conducting organic polymer materials. The bridging effect by C=C(CN)2 on the optoelectronic properties of the (carbazole-thiophene-carbazole) comonomer is investigated. Keywords: Conducting polymer; Carbazole-(Ethylenedioxythiophene)n-Carbazole comonomers; DFT Optoelectronic properties; absorption coefficient; Bridging effect. © 2012 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. doi: http://dx.doi.org/10.3329/jsr.v4i1.7450J. Sci. Res. 4 (1), 119-133 (2012)  

Monoelemental two-dimensional iodinene nanosheets: a first-principles study of the electronic and optical properties

2021 ◽  
Author(s):  
Asadollah Bafekry ◽  
C. Stampfl ◽  
M. Faraji ◽  
Bohayra Mortazavi ◽  
Mohamed Fadlallah ◽  
...  
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Blue Shift ◽  
Two Dimensional ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
Exchange Correlation ◽  
Wide Range ◽  
First Time

Abstract Very recently, two-dimensional (2D) iodinene, a novel layered and buckled structure has been successfully fabricated [Mengmeng Qian et al., Adv. Mater. (2020) 2004835]. Motivated by this latest experimental accomplishment, for the first time we conduct density functional theory, firstprinciples calculations to explore the structural, electronic, and optical properties of monolayer, few-layer and bulk iodinene. Unlike the majority of monoelemental 2D lattices, iodinene is predicted to be an intrinsic semiconductor. On the basis of calculations using the generalized gradient approximation (GGA) of Perdew-Burke-Ernzerhof (PBE) for the exchange-correlation functional and the Heyd-Scuseria-Ernzerhof (HSE06) functional, it is shown that the electronic bandgap of iodinene decreases with increasing the number of atomic layers. Our HSE06 results reveal that the bandgap of iodinene decreases from 2.08 to 1.28 eV as the number of atomic layers change from one to five, highlighting the finely tunable bandgap. The optical study shows the monolayer has the ability to absorb a wide range of ultraviolet light, more than multilayers and bulk iodinene. As the number of layers increases, the absorption spectra exhibits a blue shift relative to monolayer iodinene. This study confirms the remarkable prospect for the application of iodinene in nanoelectronics and optoelectronics owing to its intrinsic semiconducting nature.

scholarly journals Structural, Electronic and Optical properties of the Inorganic Solar Perovskites XPbBr3 (X= Li or Na)

2021 ◽  
Author(s):  
Samira Idrissi ◽  
lahoucine bahmad ◽  
a benyssef
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Density Functional ◽  
Dft Method ◽  
Lattice Parameter ◽  
Band Gap Energy ◽  
Partial Density ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
Quantum Espresso

In this paper, we study the structural, electronic and optical properties of the inorganic solar perovskites XPbBr3 (X= Li or Na). We applied the two methods: the density functional theory (DFT) and time-dependent density-functional theory (TDDFT). In fact, we performed the DFT method using the Quantum Espresso package. Also, the total energies of the studied inorganic solar perovskites XPbBr3 (X= Li or Na) have been deduced as a function of the lattice parameter a (Å). The two calculation methods have been carried out under the GGA-PBE and GGA-PBESol approximations. Moreover, the total and partial density of states (DOS) and the band structure of the studied compounds have been presented and discussed for the two cases: with and without the spin orbit coupling (SOC) approximation. In addition, the DFT and TDDFT have been explored in order to elaborate the structural, the electronic and the optical properties of the inorganic perovskite CsPbI3 material for solar cell applications. When using the GGA-PBESol method without SOC approximation, we found a band gap energy value greater than that one computed when adding the SOC correction. On the other hand, the optical properties of the studied material have been studied. In particular, we found that the inorganic solar Perovskite XPbBr3 (X=Li or Na) materials exhibit a high transparency of the electromagnetic radiations in energy range between 0 eV and 33 eV.

First principles calculation of structural, electronic and optical properties of (001) and (110) growth axis (InN)/(GaN)n superlattices

2021 ◽  
Vol 67 (1 Jan-Feb) ◽  
pp. 7
Author(s):  
B. Bachir Bouiadjra ◽  
N. Mehnane ◽  
N. Oukli
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Scale Up ◽  
Energy Scale ◽  
First Principles Calculation ◽  
Full Potential ◽  
Electronic Band ◽  
Electronic And Optical Properties ◽  
Growth Axis

Based on the full potential linear muffin-tin orbitals (FPLMTO) calculation within density functional theory, we systematically investigate the electronic and optical properties of (100) and (110)-oriented (InN)/(GaN)n zinc-blende superlattice with one InN monolayer and with different numbers of GaN monolayers. Specifically, the electronic band structure calculations and their related features, like the absorption coefficient and refractive index of these systems are computed over a wide photon energy scale up to 20 eV. The effect of periodicity layer numbers n on the band gaps and the optical activity of (InN)/(GaN)n SLs in the both  growth axis (001) and (110) are examined and compared. Because of prospective optical aspects of (InN)/(GaN)n such as light-emitting applications, this theoretical study can help the experimental measurements.

scholarly journals Electronic and optical properties of vacancy ordered double perovskites A2BX6 (A = Rb, Cs; B = Sn, Pd, Pt; and X = Cl, Br, I): a first principles study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Muhammad Faizan ◽  
K. C. Bhamu ◽  
Ghulam Murtaza ◽  
Xin He ◽  
Neeraj Kulhari ◽  
...  
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
First Principles ◽  
Density Functional ◽  
Perovskite Solar Cells ◽  
Dielectric Constants ◽  
Maximum Efficiency ◽  
Exchange Potential ◽  
Double Perovskites ◽  
Electronic And Optical Properties

AbstractThe highly successful PBE functional and the modified Becke–Johnson exchange potential were used to calculate the structural, electronic, and optical properties of the vacancy-ordered double perovskites A2BX6 (A = Rb, Cs; B = Sn, Pd, Pt; X = Cl, Br, and I) using the density functional theory, a first principles approach. The convex hull approach was used to check the thermodynamic stability of the compounds. The calculated parameters (lattice constants, band gap, and bond lengths) are in tune with the available experimental and theoretical results. The compounds, Rb2PdBr6 and Cs2PtI6, exhibit band gaps within the optimal range of 0.9–1.6 eV, required for the single-junction photovoltaic applications. The photovoltaic efficiency of the studied materials was assessed using the spectroscopic-limited-maximum-efficiency (SLME) metric as well as the optical properties. The ideal band gap, high dielectric constants, and optimum light absorption of these perovskites make them suitable for high performance single and multi-junction perovskite solar cells.

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