scholarly journals STRUCTURAL, MECHANICAL AND OPTOELECTRONIC STUDY OF DOUBLE PEROVSKITE Cs2SnBr6 USING FIRST PRINCIPLES CALCULATION

2020 ◽  
pp. 6-9
Author(s):  
MD. ABDUR RAZZAQ ◽  
TARIKUL ISLAM
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Perovskite Solar Cells ◽  
Double Perovskite ◽  
Lattice Parameter ◽  
Dielectric Constants ◽  
First Principles Calculation ◽  
Functional Theory ◽  
Direct Band ◽  
Ductile Behavior

The structural, mechanical, electronic and optical properties of double perovskite Cs2SnBr6 have been measured by density functional theory (DFT) calculations. The calculated value of lattice parameter is perfectly tailored with the experimental data. The material shows ductile behavior by Paugh’s ductility index (B/G) at ambient condition. The anisotropic nature of this compound is endorsed by the calculation of Zener anisotropy factor. The direct band gap semiconducting nature with the value of gap is 1.33 eV using PBE potential is also corroborated by electronics properties. Eventually, different optical properties of Cs2SnBr6 such as dielectric constants, refractive index, conductivity, absorption, reflectivity and loss function have been observed and disclose for radiation up to 20 eV. Finally the optical properties corroborate the optoelectronic applications of this compound as all as elite candidate for photovoltaic perovskite solar cells.

scholarly journals OPTOELECTRONIC STUDY OF DOUBLE PEROVSKITE Rb2SnBr6: A FIRST PRINCIPLES CALCULATIONS

2020 ◽  
pp. 1-5
Author(s):  
MD. ABDUR RAZZAQ ◽  
TARIKUL ISLAM
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Density Functional ◽  
Research Work ◽  
Double Perovskite ◽  
Incident Radiation ◽  
Lattice Parameter ◽  
Dielectric Constants ◽  
Ultraviolet Region ◽  
Ambient Conditions

The aim of this research work is to investigate the structural, mechanical, electronic and optical properties of double perovskite Rb2SnBr6 by density functional theory (DFT) calculations. The calculated lattice parameter is in sensible agreement with the on the market experimental information. From Paugh’s ductility index (B/G), it shows that Rb2SnBr6 is brittle at ambient conditions. The Zener anisotropy factor confirms the anisotropic nature of this compound. The calculated energy band structures indicate that Rb2SnBr6 is a direct band gap semiconductor, with the band gap of 1.228 eV using PBE potentials. In this work, the optical properties such as dielectric constants, refractive index, conductivity, extinction coefficient, loss function, and reflectivity have been studied and reported for radiation up to 20 eV. It is found that the reflectivity is about 50% in the ultraviolet (UV) region regions up to ~11 eV of incident radiation in the ultraviolet region.

Ab-initio study of structural, electronic and thermodynamic properties of Ba2YTaO6

2016 ◽  
Vol 30 (24) ◽  
pp. 1650164 ◽  
Author(s):  
Lifei Du ◽  
Huiling Du
Keyword(s):  
Thermodynamic Properties ◽  
Energy Band ◽  
Density Functional ◽  
Double Perovskite ◽  
Lattice Parameter ◽  
Generalized Gradient ◽  
Pressure Derivative ◽  
Functional Theory ◽  
Direct Band ◽  
Murnaghan Equation

The structural, electronic and thermodynamic properties of cubic double perovskite Ba2YTaO6 are calculated by using the plane wave within density functional theory (DFT) framework employing the generalized gradient approximation (GGA). The ground state quantities including the lattice parameter, bulk moduli and its pressure derivative are fitted by the Birch–Murnaghan equation of state. The calculated energy band indicates that Ba2YTaO6 has a direct band gap of 3.42 eV at [Formula: see text] point in the Brillouin zone and the energy band near Fermi level is determined by the density of states of O 2[Formula: see text], Ta 5[Formula: see text] and Y 4[Formula: see text] electrons. The thermodynamic properties including Debye temperature, bulk moduli and heat capacity of various pressures and temperatures are calculated and analyzed. Results indicate that the temperature and induced pressure have significant effect on the thermodynamic properties of Ba2YTaO6.

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.

scholarly journals First principles calculations on theoretical band gap improvement of IIIA-VA zinc-blende semiconductor InAs

2020 ◽  
Vol 31 (12) ◽  
pp. 2050178
Author(s):  
Waqas Mahmood ◽  
Arfan Bukhtiar ◽  
Muhammad Haroon ◽  
Bing Dong
Keyword(s):  
Band Gap ◽  
Density Functional ◽  
Local Density ◽  
Lattice Parameter ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Zinc Blende ◽  
Valence States ◽  
Direct Band ◽  
Experimental Findings

The structural, electronic, dielectric and vibrational properties of zinc-blende (ZB) InAs were studied within the framework of density functional theory (DFT) by employing local density approximation and norm-conserving pseudopotentials. The optimal lattice parameter, direct band gap, static dielectric constant, phonon frequencies and Born effective charges calculated by treating In-4d electrons as valence states are in satisfactory agreement with other reported theoretical and experimental findings. The calculated band gap is reasonably accurate and improved in comparison to other findings. This work will be useful for more computational studies related to semiconductor devices.

A comparative study of structural, electronic and optical properties based on metal-doped methylammonium lead halidesviafirst-principles calculations

2019 ◽  
Vol 43 (24) ◽  
pp. 9453-9457 ◽  
Author(s):  
Diwen Liu ◽  
Huijuan Jing ◽  
Rongjian Sa ◽  
Kechen Wu
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Solar Cells ◽  
Comparative Study ◽  
Density Functional ◽  
Perovskite Solar Cells ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
Metal Doped

To reduce the toxicity of Pb in perovskite solar cells, the structural stabilities, and electronic and optical properties of the mixed perovskites MAPb0.75B0.25I3(B = Mg, Ca, Sr, and Ba) were predicted using density functional theory.

Structural and optical properties of Ba3(Nb6−xTax)Si4O26 (x = 0.6, 1.8, 3.0, 4.2, 5.4)

2019 ◽  
Vol 34 (4) ◽  
pp. 331-338
Author(s):  
W. Wong-Ng ◽  
G. Y. Liu ◽  
W. F. Liu ◽  
Y. Q. Yang ◽  
S. Y. Wang ◽  
...  
Keyword(s):  
Solid Solution ◽  
Optical Properties ◽  
Density Functional ◽  
Salient Feature ◽  
Lattice Parameter ◽  
Structural And Optical Properties ◽  
Functional Theory ◽  
Coordination Environment ◽  
Distorted Octahedra ◽  
Bond Valence Sum

Structure and optical properties have been successfully determined for a series of niobium- and tantalum-containing layered alkaline-earth silicate compounds, Ba3(Nb6−xTax)Si4O26 (x = 0.6, 1.8, 3.0, 4.2, 5.4). The structure of this solid solution was found to be hexagonal P-62m (No. 189), with Z = 1. With x increases from 0.6 to 5.4, the lattice parameter a increases from 8.98804(8) to 9.00565(9) Å and c decreases from 7.83721(10) to 7.75212(12) Å. As a result, the volume decreases from 548.304(11) to 544.479(14) Å3. The (Nb/Ta)O6 distorted octahedra form continuous chains along the c-axis. These (Nb/Ta)O6 chains are in turn linked with the Si2O7 groups to form distorted pentagonal channels in which Ba ions were found. These Ba2+ ions have full occupancy and a 13-fold coordination environment with neighboring oxygen sites. Another salient feature of the structure is the linear Si–O–Si chains. When x in Ba3(Nb6−xTax)Si4O26 increases, the bond valence sum (BVS) values of the Ba sites increase slightly (2.09–2.20), indicating the size of the cage becoming progressively smaller (over-bonding). While SiO cages are also slightly smaller than ideal (BVS range from 4.16 to 4.19), the (Nb/Ta)O6 octahedral cages are slightly larger than ideal (BVS range from 4.87 to 4.90), giving rise to an under-bonding situation. The bandgaps of the solid solution members were measured between 3.39 and 3.59 eV, and the x = 3.0 member was modeled by density functional theory techniques to be 3.07 eV. The bandgaps of these materials indicate that they are potential candidates for ultraviolet photocatalyst.

scholarly journals Structural, Elastic, and Electronic Properties of Antiperovskite Chromium-Based Carbides ACCr3(A = Al and Ga)

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
D. F. Shao ◽  
W. J. Lu ◽  
S. Lin ◽  
P. Tong ◽  
Y. P. Sun
Keyword(s):  
Fermi Level ◽  
Density Functional ◽  
Ambient Pressure ◽  
Experimental Studies ◽  
Lattice Parameter ◽  
First Principles Calculation ◽  
Functional Theory ◽  
Multiple Band ◽  
A Site ◽  
Formation Energies

We theoretically investigated antiperovskite chromium-based carbides ACCr3through the first-principles calculation based on density functional theory (DFT). The structure optimization shows that the lattice parameter of ACCr3is basically proportional to the radius of A-site elements. The calculated formation energies show that AlCCr3and GaCCr3can be synthesized at ambient pressure and are stable with nonmagnetic ground states. Based on the calculation of elastic constants, some elastic, mechanical, and thermal parameters are derived and discussed. AlCCr3and GaCCr3show ductile natures and may have similar thermal properties. From the analysis of the electronic structures, it was found that there are electron and hole bands that cross the Fermi level for AlCCr3and GaCCr3, indicating multiple-band natures. The Fermi level locates at the vicinity of the density of states (DOSs) peak, which leads to a large DOS at Fermi level dominated by Cr-3d electrons. The band structures of AlCCr3and GaCCr3are very similar to those of the superconducting antiperovskite MgCNi3. The similarity may make AlCCr3and GaCCr3behave superconductively, which needs to be further investigated in theoretical and experimental studies.

Electronic structures and optical properties of IV A elements-doped 3C-SiC from density functional calculations

2018 ◽  
Vol 32 (32) ◽  
pp. 1850389 ◽  
Author(s):  
Xuefeng Lu ◽  
Tingting Zhao ◽  
Xin Guo ◽  
Meng Chen ◽  
Junqiang Ren ◽  
...  
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Electronic Structures ◽  
Density Functional ◽  
Visible Region ◽  
First Principles Calculation ◽  
Charge Difference Density ◽  
Direct Band ◽  
Density Analysis ◽  
Indirect Band Gap

Electronic structures and optical properties of IV A elements (Ge, Sn and Pb)-doped 3C-SiC are investigated by means of the first-principles calculation. The results reveal that the structure of Ge-doped system is more stable with a lower formation energy of 1.249 eV compared with those of Sn- and Pb-doped 3C-SiC systems of 3.360 eV and 5.476 eV, respectively. Doping of the IV A elements can increase the band gap, and there is an obvious transition from an indirect band gap to a direct band gap. Furthermore, charge difference density analysis proves that the covalent order of bonding between the doping atoms and the C atoms is Ge–C [Formula: see text] Sn–C [Formula: see text] Pb–C, which is fully verified by population values. Due to the lower static dielectric constant, the service life of 3C-SiC dramatically improved in production practice. Moreover, the lower reflectivity and absorption peak in the visible region, implying its wide application foreground in photoelectric devices.

scholarly journals Electronic structure and optical properties of CsI under high pressure: a first-principles study

RSC Advances ◽  
2017 ◽  
Vol 7 (83) ◽  
pp. 52449-52455 ◽  
Author(s):  
Qiang Zhao ◽  
Zheng Zhang ◽  
Xiaoping Ouyang
Keyword(s):  
Density Functional Theory ◽  
High Pressure ◽  
Optical Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Calculation Method ◽  
Density Functional ◽  
First Principles Calculation ◽  
Functional Theory ◽  
First Principles Study

We investigated the effects of high pressure on the electronic structure and optical properties of a CsI crystal through a first-principles calculation method based on density functional theory.

Establishment of Structural and Elastic Properties of Titanate Compounds Based on Pb, Sn and Ge by First-Principles Calculation

2014 ◽  
Vol 510 ◽  
pp. 57-62 ◽  
Author(s):  
N.H. Hussin ◽  
M.F.M. Taib ◽  
N.A. Johari ◽  
F.W. Badrudin ◽  
O.H. Hassan ◽  
...  
Keyword(s):  
Optical Properties ◽  
Band Structure ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Computer Code ◽  
Lattice Parameter ◽  
First Principles Calculation ◽  
Electronic Band ◽  
Equilibrium Lattice Parameter ◽  
Indirect Band Gap

Structural, electronic, and optical properties of PbTiO3, SnTiO3, and GeTiO3 tetragonals (P4mm, 99 space group) were investigated using density functional theory as implemented in pseudo-potential plane wave in CASTEP computer code. The calculated equilibrium lattice parameter, electronic band structure, and optical properties for PbTiO3 (reference compound) are in good agreement with the available experiment data. The result also shows that GeTiO3 has a higher tetragonality (c/a=1.18) compared with SnTiO3 (c/a=1.15) and PbTiO3 (c/a=1.05). Calculations of the elastic constants of PbTiO3, SnTiO3, and GeTiO3 tetragonals show that they are mechanically stable. The electronic band structure shows that PbTiO3 has higher indirect band gap at X-G compared with SnTiO3 and GeTiO3, as explained in detail by the optical properties of ATiO3 (A=Pb, Sn, Ge) through the refractive index and absorption coefficient.

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