scholarly journals Influence of Different Rotations of Organic Formamidinium Molecule on Electronic and Optical Properties of FAPbBr3 Perovskite

Coatings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1341
Author(s):  
Abdullah A. Al-Kahtani ◽  
Sobia Tabassum ◽  
Indah Raya ◽  
Ibrahim Hammoud Khlewee ◽  
Supat Chupradit ◽  
...  
Keyword(s):  
Optical Properties ◽  
Density Of States ◽  
Energy Levels ◽  
Partial Density ◽  
Spin Orbit Coupling ◽  
Electronic And Optical Properties ◽  
Hybrid Perovskite ◽  
Halide Perovskites ◽  
Soc Density ◽  
Distortion Index

Hybrid organic–inorganic halide perovskites (HOIPs) have recently represented a material breakthrough for optoelectronic applications. Obviously, studying the interactions between the central organic cation and the Pb-X inorganic octahedral could provide a better understanding of HOIPs. In this work, we used a first-principles theoretical study to investigate the effect of different orientations of central formamidinium cation (FA+) on the electronic and optical properties of FAPbBr3 hybrid perovskite. In order to do this, the band structure (with and without spin–orbit coupling (SOC)), density of states (DOS), partial density of states (PDOS), electron density, distortion index, bond angle variance, dielectric function, and absorption spectra were computed. The findings revealed that a change in the orientation of FA+ caused some disorders in the distribution of interactions, resulting in the formation of some specific energy levels in the structure. The interactions between the inorganic and organic parts in different directions create a distortion index in the bonds of the inorganic octahedral, thus leading to a change in the volume of PbBr6. This is the main reason for the variations observed in the electronic and optical properties of FAPbBr3. The obtained results can be helpful in solar-cell applications.

scholarly journals Study on Electronic and Optical Properties of Graphene Oxide Under an External Electric Field From First-principles

2021 ◽  
Author(s):  
Abdehafid Najim ◽  
Omar BAJJOU ◽  
Mustapha BOULGHALLAT ◽  
Mohammed Khenfouch ◽  
Khalid Rahmani
Keyword(s):  
Optical Properties ◽  
Graphene Oxide ◽  
Electric Field ◽  
Band Gap ◽  
External Electric Field ◽  
Density Of States ◽  
Density Functional ◽  
Partial Density ◽  
Total Density ◽  
Electronic And Optical Properties

Abstract Electronic and optical properties of graphene oxide (GO), under an external electric field (Eext) applied in three directions of space (x, y, z), are investigated using the density functional theory (DFT). The application of the Eext, causes a significant modifications to the electronic and optical properties of GO material. It has change the band gap, total density of states (TDOS), partial density of states (PDOS), absorption coefficient (α), dielectric function, optical conductivity, refractive index and loss function. The band gap of GO layer increases under the effects of the Eext, applied in x and y directions. On the other hand, for z direction, the band gap decreases by the effects of the Eext. The peaks of the TDOS around the Fermi level, change by the Eext applied in (x, y, z) directions. The α peaks of the GO sheet, decreases by the Eext applied in x direction, and increases if Eext applied in y and z directions. It is found that, the electronic and optical properties of GO layer, could be affected by the effects of the Eext and by its direction of application.

scholarly journals Electronic and Optical Properties of Mg2GeO4 Under Pressure Effect: ab Initio Study

2021 ◽  
Author(s):  
Yunxia Zhang ◽  
Li’na Xiao
Keyword(s):  
Optical Properties ◽  
Density Of States ◽  
Pressure Dependence ◽  
Mechanical Stability ◽  
Electronic Band Structure ◽  
Structural Parameters ◽  
Partial Density ◽  
Band Structures ◽  
Electronic Band ◽  
Electronic And Optical Properties

Abstract We report first-principles studies the structural, elastic, electronic, and optical properties of Mg2GeO4 in orthorhombic structure, including pressure dependence of structural parameters, band structures, density of states, and optical constants up to 20 GPa. The calculated structural parameters are in good agreement with the available experimental values at zero pressure. The mechanical stability of Mg2GeO4 has been confirmed by calculation of the elastic constants. And the non-uniform pressure dependence of the lattice parameters may also mean that Mg2GeO4 undergoes anisotropic compression. Meanwhile, the pressure dependence of the electronic band structure, density of states and partial density of states of Mg2GeO4 up to 20 GPa were presented. The band structures show a direct band gap for this compound and the calculated band gaps expend with increasing pressure. Moreover, the evolution of the dielectric function, absorption coefficient (α(ω)), reflectivity (R(ω)), and the real part of the refractive index (n(ω)) at high pressure are also presented. According to our work, we found that the optical properties of Mg2GeO4 undergo a blue shift with increasing pressure.

First-Principles Study of Electronic Structure and Optical Properties of V-Doped CrSi2

2015 ◽  
Vol 1104 ◽  
pp. 125-130 ◽  
Author(s):  
Fang Gui ◽  
Shi Yun Zhou ◽  
Wan Jun Yan ◽  
Chun Hong Zhang ◽  
Shao Bo Chen
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Density Of States ◽  
Density Functional ◽  
Partial Density ◽  
Optical Parameters ◽  
Total Density ◽  
Type Semiconductor ◽  
Refractive Index Increase ◽  
P Type

The electronic structure and optical properties of V-doped CrSi2 have been calculated by using the first-principle peudo-potential plane-wave method based on the density functional theory.The parameters and properties of structure were given and the theory data were offered to research the effect of V doping into CrSi2. The calculations of energy band structure, total density of states, partial density of states of V-doped CrSi2were analysed. Fermi level enters into valence band which makes the V-doped CrSi2to be p-type semiconductor that improves the electrical conductivity of material. Additionally, the optical parameters of V-doped CrSi2were also discussed. It was found that both static dielectric constant and static refractive index increase after doping.

Ab initio study of oxygen vacancy effects on electronic and optical properties of NiO

MRS Advances ◽  
2016 ◽  
Vol 1 (37) ◽  
pp. 2617-2622 ◽  
Author(s):  
John Petersen ◽  
Fidele Twagirayezu ◽  
Pablo D. Borges ◽  
Luisa Scolfaro ◽  
Wilhelmus Geerts
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Local Density ◽  
Optical Transition ◽  
Energy Levels ◽  
Density Functional Theory Calculations ◽  
Local Density Of States ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
O Vacancy

ABSTRACTDensity Functional Theory calculations of electronic and optical properties of NiO, with and without O vacancies, are the focus of this work. Two bands, one fully occupied and the other unoccupied, induced by an O vacancy, are found in the gap. These energy levels are identified and analyzed by means of a local density of states (LDOS) calculation, and notable crystal field splitting can be seen. The real and imaginary parts of the dielectric function are calculated, and an additional optical transition can be seen at lower energy, which can be attributed to the O vacancy induced state in the band gap.

Exploration on electronic and optical properties of two-dimensional GaN-doped with Be, Mg, Zn

2020 ◽  
Vol 34 (20) ◽  
pp. 2050195
Author(s):  
Gang Li ◽  
Lei Liu ◽  
Jian Tian
Keyword(s):  
Optical Properties ◽  
Band Structure ◽  
Density Of States ◽  
First Principles ◽  
High Energy ◽  
Low Energy ◽  
Two Dimensional ◽  
Electronic And Optical Properties ◽  
Type Semiconductor ◽  
P Type

To explore the variation on p-type-doped two-dimensional GaN, we calculate electronic and optical properties of buckled two-dimensional GaN-doped with p-type doping elements including Be, Mg and Zn atom by using first-principles. The results indicate that doping process of two-dimensional GaN after Be is most easily compared with Mg- and Zn-doped models. Band of doped two-dimensional GaN moves toward high energy end and it becomes a p-type semiconductor from the results of band structure and density of states, which may be caused by orbitals hybridization from dopants. Band gap and work function of doped two-dimensional GaN are both declined, which is beneficial for escape of electrons. Analysis of optical properties shows that they are sensitive and adjustable in doped two-dimensional GaN. Doping of Be, Mg and Zn atoms would have an important effect on optical characteristics of two-dimensional GaN at low-energy region.

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