scholarly journals First–Principles Investigation of the Structural, Elastic, Electronic, and Optical Properties of α– and β–SrZrS3: Implications for Photovoltaic Applications

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 978
Author(s):  
Henry Igwebuike Eya ◽  
Esidor Ntsoenzok ◽  
Nelson Y. Dzade
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Visible Region ◽  
Charge Carriers ◽  
Band Gaps ◽  
Strong Light ◽  
Electronic And Optical Properties ◽  
Optical Absorbance ◽  
Effective Masses

Transition metal perovskite chalcogenides are attractive solar absorber materials for renewable energy applications. Herein, we present the first–principles screened hybrid density functional theory analyses of the structural, elastic, electronic and optical properties of the two structure modifications of strontium zirconium sulfide (needle–like α–SrZrS3 and distorted β–SrZrS3 phases). Through the analysis of the predicted electronic structures, we show that both α– and β–SrZrS3 materials are direct band gaps absorbers, with calculated band gaps of 1.38, and 1.95 eV, respectively, in close agreement with estimates from diffuse–reflectance measurements. A strong light absorption in the visible region is predicted for the α– and β–SrZrS3, as reflected in their high optical absorbance (in the order of 105 cm−1), with the β–SrZrS3 phase showing stronger absorption than the α–SrZrS3 phase. We also report the first theoretical prediction of effective masses of photo-generated charge carriers in α– and β–SrZrS3 materials. Predicted small effective masses of holes and electrons at the valence, and conduction bands, respectively, point to high mobility (high conductivity) and low recombination rate of photo-generated charge carriers in α– and β–SrZrS3 materials, which are necessary for efficient photovoltaic conversion.

scholarly journals Electronic and optical properties of Ba(1-x)Ca(x) TiO3 and Ba(1-x)Sr(x)TiO3

2018 ◽  
Vol 3 (1) ◽  
Author(s):  
A. Belaaraj ◽  
O. Tahiri ◽  
S. Kassou ◽  
R. El Mrabet
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Low Energy ◽  
Band Gaps ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
Densities Of States ◽  
Indirect Band Gap

The effect of Ca and Sr-doping on the structural electronic and optical properties of the cubic Ba1-xCaxTiO3 and Ba1-xSrxTiO3 (x=0.4, 0.6) mixed crystals was investigated using first-principles calculations based on density functional theory (DFT). The calculated band structures based on the optimized geometry of the cell for the solid solutions show an indirect band gap character at M-points, with low energy dispersion along height symmetry directions in the Brillouin zone. The band gaps increase with Ca and Sr concentrations. The total and partial densities of states were analyzed to examine the contribution of different orbitals to the maximum of valence band and the minimum of the conduction band. The optical properties such as reflectivity, energy loss, refractive index and extinction coefficient were studied. #DFT_calculations #band_gap #density_of_states #optical_properties

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.

Electronic and optical properties of zinc-blende GeC by first principles study

2015 ◽  
Vol 29 (20) ◽  
pp. 1550103
Author(s):  
Jinhui Zhai ◽  
Jinguang Zhai ◽  
Ajun Wan
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Dielectric Constants ◽  
Electronic And Optical Properties ◽  
Optical Functions ◽  
Zinc Blende ◽  
The Density Functional Theory ◽  
Valence Bands ◽  
Energy Dependent

The electronic and optical properties of zinc-blende (zb)[Formula: see text]GeC have been investigated using first principles calculations based on the density functional theory (DFT). The obtained band gap of zb–GeC is 2.30[Formula: see text]eV by means of Heyd–Scuseria–Ernzerhof (HSE) functional. We have discussed the energy-dependent optical functions including dielectric constants, refractive index, absorption, reflectivity, and energy-loss spectrum in detail. The results reveal that zb–GeC has a higher static dielectric constant compared with that of zb–SiC. The optical functions are mainly associated with the interband transitions from the occupied valence bands (VBs) Ge[Formula: see text][Formula: see text] and C[Formula: see text][Formula: see text] states to Ge[Formula: see text][Formula: see text], [Formula: see text] and C[Formula: see text][Formula: see text] states of the unoccupied conduction bands (CBs).

scholarly journals First principles study of structure, electronic and optical properties of Y3Fe5O12 in cubic and trigonal phases

2015 ◽  
Vol 33 (1) ◽  
pp. 169-174 ◽  
Author(s):  
Shen Tao ◽  
Hu Chao ◽  
Dai Hailong ◽  
Yang Wenlong ◽  
Liu Hongchen ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Energy Loss ◽  
First Principles ◽  
Structural Parameters ◽  
Band Gaps ◽  
First Principles Calculations ◽  
Electronic And Optical Properties ◽  
Direct Band ◽  
Experimental Values

AbstractFirst principles calculations have been performed to investigate the structure, electronic and optical properties of Y3Fe5O12. Both the cubic and trigonal phases have been considered in our calculation. The calculated structural parameters are slightly larger than the experimental values. The band structures show that Y3Fe5O12 in cubic and trigonal phases have direct band gaps of 0.65 and 0.17 eV. The calculations of dielectric function, absorption, extinction coefficient, refractive index, energy loss function and reflectivity are presented.

Electronic and Optical Properties of Indium Selenide Nanosheet Using First-Principle Calculations

2019 ◽  
Vol 11 (11) ◽  
pp. 1148-1154
Author(s):  
Hamza A. Mezerh ◽  
Kadhim J. Kadhim ◽  
Hamad Rahman Jappor
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Density Functional ◽  
Visible Region ◽  
High Refractive Index ◽  
Indium Selenide ◽  
Experimental Investigations ◽  
Ultraviolet Region ◽  
Electronic And Optical Properties ◽  
Index Value

Density functional theory (DFT) have been used to examine the electronic and optical, properties of two-dimensional (2D) indium selenide (InSe) nanosheet. Our calculations indicate that the energy band gap of InSe is indirect and equal to 1.53 eV. It can be seen that for the pristine case, the majority and minority density of state (DOS) are fully symmetric. The optical properties are considered up to 36 eV. Our results established that the absorption starts in the visible region, while the peaks in the ultraviolet region. The refractive index value is 1.84 at zero photon energy limit and increase to 2.31. The high refractive index allows this nanosheet to be utilized as an internal layer coating between the substrate and the ultraviolet absorbing layer. Additionally, we observed that the gained optical properties of InSe nanosheet are in the ultraviolet range and the results are significant. It is expected that from these calculations to provide useful information for further experimental investigations of InSe nanosheet.

Electronic Structure, Effective Masses and Optical Properties of Monoclinic HfO2 from First-Principles Calculations

2011 ◽  
Vol 216 ◽  
pp. 341-344 ◽  
Author(s):  
Qi Jun Liu ◽  
Zheng Tang Liu ◽  
Li Ping Feng
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Band Structure ◽  
First Principles ◽  
Density Functional ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Effective Masses ◽  
Indirect Band Gap ◽  
Calculated Equilibrium

Electronic structure, effective masses and optical properties of monoclinic HfO2were studied using the plane-wave ultrasoft pseudopotential technique based on the first-principles density-functional theory (DFT). The calculated equilibrium lattice parameters are in agreement with the previous works. From the band structure, the effective masses and optical properties are obtained. The calculated band structure shows that monoclinic HfO2has indirect band gap and all of the effective masses of electrons and holes are less than that of a free electron. The peaks position distributions of imaginary parts of the complex dielectric function have been explained according to the theory of crystal-field and molecular-orbital bonding.

First Principles Studies on Structural, Electronic and Optical Properties of SnO2

2014 ◽  
Vol 900 ◽  
pp. 203-208 ◽  
Author(s):  
Ting Ting Shao ◽  
Fu Chun Zhang ◽  
Wei Hu Zhang
Keyword(s):  
Experimental Data ◽  
Density Functional Theory ◽  
Optical Properties ◽  
Plane Wave ◽  
Qualitative Analysis ◽  
First Principles ◽  
Density Functional ◽  
Density Of State ◽  
Functional Theory ◽  
Electronic And Optical Properties

The structural, electronic, and optical properties of rutile-type SnO2 are studied by plane-wave pseudopotential density functional theory (DFT) with GGA, LDA, B3LYP and PBE0 respectively. The computing results show that the band gap getting from PBE0 and B3LYP is much more consistent with the available experimental data than that from GGA and LDA, no matter what the latter use ultra-soft pseudopotential or norm conserving pseudopotential. However, the density of state, real part and imaginary part of dielectric function calculating from every type is basically similar in qualitative analysis.

scholarly journals Structural, Electronic and Optical Properties of Cubic Perovskite Cspbx3 (X= Br, Cl and I)

2020 ◽  
Vol 8 (1) ◽  
pp. 23-28
Author(s):  
Aawzad A. Abdulkareem ◽  
Sarkawt A. Sami ◽  
Badal H. Elias
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Structural Parameters ◽  
Plane Waves ◽  
Experimental Studies ◽  
Visible Region ◽  
Electromagnetic Spectrum ◽  
Generalized Gradient ◽  
Electronic And Optical Properties ◽  
Low Energies

Plane waves with norm conserving pseudopotentials (PW-PP) method in conjunction with density functional theory (DFT) frame work have been used to investigate structural, electronic and optical properties of lead-halide cubic perovskite CsPbX3 (X=Br, Cl and I). The generalized gradient approximation (GGA), specifically Perdew-Burke-Ernzerhof (PBE) flavor, has been chosen to treat the exchange correlation term of Kohn-Sham equation. Structural parameters are comparable with other theoretical and experimental studies. In spite of good agreement of our band gap values  with other theoretical works, however, they were not comparable when compared to the experimental  values due to the well-known problem of Eg value underestimation of DFT. To update the  value, we have used GW method as a self-consistent quasiparticle method on energies and wave functions and indeed they have been improved. Optical properties have been calculated using density functional perturbation theory (DFPT). Our results show that CsPbX3 (X=Br, Cl, I) has maximum response to the electromagnetic spectrum at low energies (visible region) but minimum response at high energies.

First-principles calculations to investigate structural, electronic and optical properties of (ZnSe)n/(ZnTe)n superlattices

2020 ◽  
Author(s):  
Messaoud Caid
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Correlation Energy ◽  
Local Density ◽  
Full Potential ◽  
First Principles Calculations ◽  
Electronic And Optical Properties ◽  
Lmto Method ◽  
Binary Compounds

An investigation into the structural, electronic and optical properties of superlattices(SLs) (ZnSe)n/(ZnTe)n was conducted using first principles calculations based on density functional theory (DFT). The total energies were calculated within the full-potential linear muffin-tin orbital (FP-LMTO) method augmented by a plane-wave basis (PLW), implemented in LmtART 7.0 code. The effects of the approximations to the exchange-correlation energy were treated by the local density approximation (LDA). The ground state properties of (ZnSe)n/(ZnTe)n binary compounds are determined and compared with the available data. It is found that the superlattice (n-n: 1-1, 2-2 and 3-3) band gaps vary depending on the layers used. The optical constants, including the dielectric function ε(w), the refractive index n(w) and the reflectivity R(w), are calculated for radiation energies up to 35eV.

SiGe/h-BN heterostructure with inspired electronic and optical properties: a first-principles study

2016 ◽  
Vol 4 (42) ◽  
pp. 10082-10089 ◽  
Author(s):  
Xianping Chen ◽  
Xiang Sun ◽  
D. G. Yang ◽  
Ruishen Meng ◽  
Chunjian Tan ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
First Principles Study

The structure along with the electronic and optical properties of a SiGe/BN monolayer heterostructure were theoretically researched using density functional theory calculations.

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