scholarly journals Electronic and optical properties of bulk and surface of CsPbBr3 inorganic halide perovskite a first principles DFT 1/2 approach

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohammed Ezzeldien ◽  
Samah Al-Qaisi ◽  
Z. A. Alrowaili ◽  
Meshal Alzaid ◽  
E. Maskar ◽  
...  
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Visible Spectrum ◽  
Ultra Violet ◽  
Electronic And Optical Properties ◽  
Direct Band ◽  
Halide Perovskites ◽  
Electro Magnetic ◽  
Experimental Findings ◽  
Lead Halide

AbstractThis work aims to test the effectiveness of newly developed DFT-1/2 functional in calculating the electronic and optical properties of inorganic lead halide perovskites CsPbBr3. Herein, from DFT-1/2 we have obtained the direct band gap of 2.36 eV and 3.82 eV for orthorhombic bulk and 001-surface, respectively. The calculated energy band gap is in qualitative agreement with the experimental findings. The bandgap of ultra-thin film of CsPbBr3 is found to be 3.82 eV, which is more than the expected range 1.23-3.10 eV. However, we have found that the bandgap can be reduced by increasing the surface thickness. Thus, the system under investigation looks promising for optoelectronic and photocatalysis applications, due to the bandgap matching and high optical absorption in UV–Vis (Ultra violet and visible spectrum) range of electro-magnetic(em) radiation.

scholarly journals Computational Investigation of the Folded and Unfolded Band Structure and Structural and Optical Properties of CsPb(I1−xBrx)3 Perovskites

Crystals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 342 ◽  
Author(s):  
Hamid M. Ghaithan ◽  
Zeyad A. Alahmed ◽  
Andreas Lyras ◽  
Saif M. H. Qaid ◽  
Abdullah S. Aldwayyan
Keyword(s):  
Optical Properties ◽  
Band Structure ◽  
Band Gap ◽  
Spectral Weight ◽  
Band Gap Energy ◽  
Full Potential ◽  
Generalized Gradient ◽  
Electronic And Optical Properties ◽  
Generalized Gradient Approximation ◽  
Direct Band

The structural, electronic, and optical properties of inorganic CsPb(I1−xBrx)3 compounds were investigated using the full-potential linear augmented-plane wave (FP-LAPW) scheme with a generalized gradient approximation (GGA). Perdew–Burke–Ernzerhof generalized gradient approximation (PBE-GGA) and modified Becke–Johnson GGA (mBJ-GGA) potentials were used to study the electronic and optical properties. The band gaps calculated using the mBJ-GGA method gave the best agreement with experimentally reported values. CsPb(I1−xBrx)3 compounds were wide and direct band gap semiconductors, with a band gap located at the M point. The spectral weight (SW) approach was used to unfold the band structure. By substituting iodide with bromide, an increase in the band gap energy (Eg) values of 0.30 and 0.55 eV, using PBE-GGA and mBJ-GGA potentials, respectively, was observed, whereas the optical property parameters, which were also investigated, demonstrated the reverse effect. The high absorption spectra in the ultraviolet−visible energy range demonstrated that CsPb(I1−xBrx)3 perovskite could be used in optical and optoelectronic devices by partly replacing iodide with bromide.

First-Principle Study of the Structural, Electronic, and Optical Properties of Cubic Cesium Lead Halide Perovskites for Photovoltaic System

2020 ◽  
Vol 4 (2) ◽  
pp. 1-16
Author(s):  
Muhammad Waqas
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Density Functional ◽  
Covalent Bond ◽  
Wide Band ◽  
Photovoltaic System ◽  
Full Potential ◽  
Potential Applications ◽  
Halide Perovskites ◽  
Lead Halide

Lead halide perovskites have attracted considerable attention as optoelectronic materials because these materials have high photovoltaic conversion efficiency. The current study is based on Density Functional Theory (DFT). This theory was used to calculate the structural, optical, and electronic properties of the lead halide perovskites CsPbX3 (X = Chlorine (Cl), Bromine (Br), Iodine (I)) compounds . In order to calculate the above mentioned properties of cubic perovskites CsPbX3 (X = Cl, Br, I), Full Potential Linear Augmented Plane Wave (FP-LAPW) method was implemented in conjunction with DFT utilizing LDA, GGA-PBE and mBJ approximations. A good agreement was found between experimentally measured values and theoretically calculated lattice constants. These compounds have a direct and wide band gap located at the point of R-symmetry, while the band gap decreases from ‘Cl’ to ‘I’ down the group. The densities of electrons revealed a strong ionic bond between Cs and halides and a strong covalent bond between ‘Pb’ and (Cl, Br, and I). The dielectric functions (reflectivity, refractive indices, absorption coefficients), optical conductivities (real and imaginary part) and other optical properties indicated that these compounds have novel energy harvester applications. The modeling of these perovskite compounds shows that they have high absorption power and direct band gaps in visible ultraviolet range and it also shows that these compounds have potential applications in solar cells.

scholarly journals Stable GaSe-Like Phosphorus Carbide Monolayer with Tunable Electronic and Optical Properties from Ab Initio Calculations

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1937 ◽  
Author(s):  
Xiaolin Cai ◽  
Zhili Zhu ◽  
Weiyang Yu ◽  
Chunyao Niu ◽  
Jianjun Wang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Electronic Structures ◽  
Density Functional ◽  
Promising Candidate ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
Direct Band Gap ◽  
Direct Band ◽  
Indirect Band Gap

On the basis of density functional theory (DFT) calculations, we propose a stable two-dimensional (2D) monolayer phosphorus carbide (PC) with a GaSe-like structure, which has intriguing electronic and optical properties. Our calculated results show that this 2D monolayer structure is more stable than the other allotropes predicted by Tománek et al. [Nano Lett., 2016, 16, 3247–3252]. More importantly, this structure exhibits superb optical absorption, which can be mainly attributed to its direct band gap of 2.65 eV. The band edge alignments indicate that the 2D PC monolayer structure can be a promising candidate for photocatalytic water splitting. Furthermore, we found that strain is an effective method used to tune the electronic structures varying from direct to indirect band-gap semiconductor or even to metal. In addition, the introduction of one carbon vacancy in such a 2D PC structure can induce a magnetic moment of 1.22 µB. Our findings add a new member to the 2D material family and provide a promising candidate for optoelectronic devices in the future.

scholarly journals Computational studies on electronic and optical properties of dopamine derivatives structure: A DFT study**

2021 ◽  
Vol 30 (1) ◽  
pp. 279-284
Author(s):  
Mohammed L. Jabbar
Keyword(s):  
Optical Properties ◽  
Visible Spectrum ◽  
Ultra Violet ◽  
Dielectric Behavior ◽  
Dft Methods ◽  
Electronic And Optical Properties ◽  
Sensor Applications ◽  
Dopamine Quinone ◽  
Td Dft ◽  
Electronic Affinity

Abstract Dopamine is considered an important molecule that plays several essential roles in the human body, and herein lies the key to this paper on the electronic and optical properties of dopamine and its derivatives, such as quinone and L-dihydroxyphenylalanine (L-DOPA), using DFT and TD-DFT methods, respectively. Our findings show that dopamine has a dielectric behavior, whereas quinone and L-DOPA have semiconductor behaviors in the ground and excited states. By computing the optical properties, we disclose that the electronic transition spectrum of dopamine, quinone and L-DOPA are observed in the ultra-violet region, visible spectrum, and (ultraviolet and visible regions), respectively. Other properties, such as ionization potential, electronic affinity, hardness and softness are also calculated due to their importance in sensor applications and sensing.

scholarly journals Structural, Electronic and Optical Properties of InAs Phases: By GGA-PBG and GGA-EV Approximations

2017 ◽  
Vol 41 (3) ◽  
pp. 172-182
Author(s):  
Leila Sohrabi ◽  
Arash Boochani ◽  
S. Ali Sebt ◽  
S. Mohammad Elahi
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Density Functional ◽  
Photonic Devices ◽  
Optical Parameters ◽  
Full Potential ◽  
Electronic Band ◽  
Electronic And Optical Properties ◽  
Direct Band ◽  
Electronic Band Gap

Structural, electronic and optical properties of InAs are investigated in the zinc-blende (ZB), rock-salt (RS) and wurtzite (WZ) phases using the full potential linearised augmented plane wave method in the framework of density functional theory (DFT). The electronic band gap of the ZB and WZ phases are improved and in good agreement with experiments by GGA-EV approximation. This compound has a direct band gap in the ZB and WZ phases in point at the centre Brillouin zone and in the RS phase the conduction band crosses towards the valence band and has metallic behaviour. Also, the optical parameters such as the real and imaginary parts of epsilon, energy loss, and the refraction and reflection indices of all the phases are calculated and compared. The calculated optical properties of InAs have promising applications such as the design of optoelectronic and photonic devices.

AB INITIO STUDY OF STRUCTURAL, ELECTRONIC AND OPTICAL PROPERTIES OF MgxCd1-xX (X = S, Se, Te) ALLOYS

2012 ◽  
Vol 26 (30) ◽  
pp. 1250168 ◽  
Author(s):  
N. A. NOOR ◽  
A. SHAUKAT
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Ternary Alloys ◽  
Full Potential ◽  
Generalized Gradient ◽  
Calculated Density ◽  
Electronic And Optical Properties ◽  
Direct Band

This study describes structural, electronic and optical properties of Mg x Cd 1-x X (X = S, Se, Te) alloys in the complete range 0≤x ≤1 of composition x in the zinc-blende (ZB) phase with the help of full-potential linearized augmented plane wave plus local orbitals (FP-LAPW+lo) method within density functional theory (DFT). In order to calculate total energy, generalized gradient approximation (Wu–Cohen GGA) has been applied, which is based on optimization energy. For electronic structure calculations, the corresponding potential is being optimized by Engel–Vosko GGA formalism. Our calculations reveal the nonlinear variation of lattice constant and bulk modulus with different concentration for the end binary and their ternary alloys, which slightly deviates from Vegard's law. The calculated band structures show a direct band gap for all three alloys with increasing order in the complete range of the compositional parameter x. In addition, we have discussed the disorder parameter (gap bowing) and concluded that the total band gap bowing is substantially influenced by the chemical (electronegativity) contribution. The calculated density of states (DOS) of these alloys is discussed in terms of contribution from various s-, p- and d-states of the constituent atoms and charge density distributions plots are analyzed. Optical properties have been presented in the form of the complex dielectric function ε(ω), refractive index n(ω) and extinction coefficient k(ω) as function of the incident photon energy, and the results have been compared with existing experimental data and other theoretical calculations.

2D Hexagonal SnTe monolayer: a quasi direct band gap semiconductor with strain sensitive electronic and optical properties

2020 ◽  
Vol 93 (2) ◽  
Author(s):  
Negin Fatahi ◽  
D. M. Hoat ◽  
Amel Laref ◽  
Shorin Amirian ◽  
A. H. Reshak ◽  
...  
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Electronic And Optical Properties ◽  
Direct Band Gap ◽  
Direct Band

Electronic and optical properties of Janus Monolayers MoXB2(X=S,Se): First-principles prediction

2021 ◽  
Author(s):  
Qingwen Lan ◽  
Changpeng Chen ◽  
Tian Qin
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
First Principles ◽  
First Principles Calculations ◽  
Electronic And Optical Properties ◽  
Direct Band Gap ◽  
Direct Band ◽  
Indirect Band Gap ◽  
The Stability ◽  
Optical Calculation

By means of comprehensive first-principles calculations, we studied the geometric structure, the stability and electronic properties of the new two-dimensional(2D) Janus MoXB2(X=S, Se) monolayers. Our calculations demonstrated that the predicted Janus MoXB2 monolayers are all stable semiconductors with direct band gap. In this paper, we focus on impacts upon the electronic and optical properties of the MoXB2 monolayers under the different biaxial strains. With the compressive stress increases, the MoXB2 monolayers would become indirect band gap semiconductors, and then behave as semimetal. While under tensile strain, MoXB2 still maintain direct band gap. In addition, the optical calculation shows that biaxial strain leads to blue shifts in the optical absorption and reflectivity. The result indicates that MoXB2 may be promised nano candidate materials in optoelectronic devices.

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