Elastic and electronic properties of oxygen plasma-treated graphene sheets from first principles

2017 ◽  
Vol 31 (08) ◽  
pp. 1750054
Author(s):  
F. Nasehnia ◽  
M. Seifi
Keyword(s):  
Electronic Properties ◽  
Elastic Constants ◽  
Density Functional ◽  
Oxygen Plasma ◽  
Graphene Sheets ◽  
Pristine Graphene ◽  
Functional Theory ◽  
Compressive Loads ◽  
C 50 ◽  
Special Case

Mechanical and electronic properties of oxygen plasma-treated graphene sheets are investigated using density functional theory (DFT). Oxygen plasma-treated graphene is modeled using a graphene sheet with adsorbed epoxide functional groups (C–O–C) on its one side. The most stable configurations of such oxidized graphene sheets with different O/C ratios ranging from 12.5% to 50% are then calculated. In the special case of O/C = 50% (fully oxidized surface), both single- and double-sided oxidation cases are considered. The elastic and electronic properties of the energetically most favorable configurations are evaluated under the tensile and compressive loads in harmonic range. For structures with high O/C ratios (O/C [Formula: see text] 25%), the elastic constants (modulus of elasticity and bulk modulus) are significantly smaller than those of graphene while for low O/C ratios (O/C [Formula: see text] 12.5%), these quantities are almost equal to the elastic constants of pristine graphene. We also found that the electronic bandgap of the oxidized sheets is increased under tensile loading.

scholarly journals Tunable Electronic Properties of Nitrogen and Sulfur Doped Graphene: Density Functional Theory Approach

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 268 ◽  
Author(s):  
Ji Lee ◽  
Sung Kwon ◽  
Soonchul Kwon ◽  
Min Cho ◽  
Kwang Kim ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Band Structure ◽  
Fermi Level ◽  
Electronic Properties ◽  
Density Functional ◽  
Pristine Graphene ◽  
Theory Approach ◽  
Functional Theory ◽  
Doped Graphene ◽  
P Type

We calculated the band structures of a variety of N- and S-doped graphenes in order to understand the effects of the N and S dopants on the graphene electronic structure using density functional theory (DFT). Band-structure analysis revealed energy band upshifting above the Fermi level compared to pristine graphene following doping with three nitrogen atoms around a mono-vacancy defect, which corresponds to p-type nature. On the other hand, the energy bands were increasingly shifted downward below the Fermi level with increasing numbers of S atoms in N/S-co-doped graphene, which results in n-type behavior. Hence, modulating the structure of graphene through N- and S-doping schemes results in the switching of “p-type” to “n-type” behavior with increasing S concentration. Mulliken population analysis indicates that the N atom doped near a mono-vacancy is negatively charged due to its higher electronegativity compared to C, whereas the S atom doped near a mono-vacancy is positively charged due to its similar electronegativity to C and its additional valence electrons. As a result, doping with N and S significantly influences the unique electronic properties of graphene. Due to their tunable band-structure properties, the resulting N- and S-doped graphenes can be used in energy and electronic-device applications. In conclusion, we expect that doping with N and S will lead to new pathways for tailoring and enhancing the electronic properties of graphene at the atomic level.

scholarly journals Influence of Isostatic Pressure on the Elastic and Electronic Properties of K2SiF6:Mn4+

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 613
Author(s):  
Mekhrdod Subhoni ◽  
Umar Zafari ◽  
Chong-Geng Ma ◽  
Alok M. Srivastava ◽  
William W. Beers ◽  
...  
Keyword(s):  
Electronic Properties ◽  
Elastic Constants ◽  
Density Functional ◽  
Pressure Effects ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Crystal Field Strength ◽  
Equation Of States ◽  
Strain Relationship ◽  
The Relationship

Isostatic pressure effects on the elastic and electronic properties of non-doped and Mn4+-doped K2SiF6 (KSF) have been investigated by first-principles calculations within density functional theory (DFT). Bulk modulus was obtained by the Murnaghan’s equation of states (EOS) using the relationship between volume and pressures at pressures between 0 and 40 GPa, and elastic constants were calculated by the stress–strain relationship giving small distortions at each pressure point. The other elastic parameters such as shear modulus, sound velocity and Debye temperature, which can be obtained from the elastic constants, were also estimated. The influence of external isostatic pressure on the electronic properties, such as crystal field strength 10Dq and emission energy of 2E → 4A2 transition (Eem), of KSF:Mn4+ was also studied. The results suggest that 10Dq and Eem linearly increase and decrease, respectively, with increasing pressure.

Hydrogen storage on palladium adsorbed graphene: A density functional theory study

2015 ◽  
Vol 29 (20) ◽  
pp. 1550143 ◽  
Author(s):  
Nurapati Pantha ◽  
Asim Khaniya ◽  
Narayan Prasad Adhikari
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
Pristine Graphene ◽  
Geometrical Structures ◽  
Functional Theory ◽  
London Dispersion ◽  
The Stability ◽  
Quantum Espresso

We have performed density functional theory (DFT)-based first-principles calculations to study the stability, geometrical structures, and electronic properties of a single palladium (Pd) atom adsorbed graphene with reference to pristine graphene. The study also covers the adsorption properties of molecular hydrogen/s on the most stable Pd-graphene geometry by taking into account London dispersion forces in addition to the standard DFT calculations in the Quantum ESPRESSO package. From the analysis of estimated values of binding energy of Pd on different occupation sites (i.e., bridge, hollow, and top) of graphene supercells, the bridge site is found to be the most favorable one with the magnitudes of 1.114, 1.426, and 1.433 eV in 2×2, 3×3, and 4×4 supercells, respectively. The study of the electronic properties of Pd adsorbed graphene shows a bandgap of 45 meV, which can account for the breaking of the symmetry of the graphene structure. Regarding the gaseous (hydrogen) adsorption on Pd-adatom graphene, we checked the increasing number of molecular hydrogens ( H 2) from one to seven on the 3×3 supercell, and found that the adsorption energy per H 2 decreases on increasing hydrogen concentration and lies within the range of 0.998–0.151 eV.

scholarly journals Comprehensive analysis of electronic properties due to N, O, Be, and B elements doped and adsorbed on graphene from DFT calculations

2021 ◽  
Author(s):  
Gaurav Raj ◽  
Hud Wahab ◽  
Patrick A. Johnson ◽  
Dilpuneet S. Aidhy
Keyword(s):  
Dft Calculations ◽  
Electronic Properties ◽  
Density Functional ◽  
Doping Concentration ◽  
Comprehensive Analysis ◽  
Pristine Graphene ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Substitutional Doping ◽  
Correction Terms

Abstract Doping and adsorption of impurities affect the electronic properties of graphene. In this paper, using density functional theory (DFT) calculations, we present a comprehensive analysis of the effects of substitutional doping as well as atomic and diatomic adsorption on the electronic properties in graphene. Four elements, i.e., N, O, Be and B are considered. We find that (1) the substitutional doping with either of the four elements results in opening of the bandgap, and the bandgap increases with increase in the doping concentration. (2) The N, O and B atoms chemisorb on the graphene surface and open the bandgap, whereas Be atom physisorbs without changing the bandgap of pristine graphene. (3) Diatomic N2 and O2 physisorb on graphene and do not alter the bandgap, whereas both Be2 and B2 chemisorb on graphene but only B2 opens the band gap. The differences in the properties due to LDA and GGA exchange-correlation functionals, van der Waals correction terms, and system sizes are also presented. These results are compared with the existing literature, and possible underlying reasons for the existing significant discrepancies among literature are discussed.

scholarly journals Defect Processes in Halogen Doped SnO2

2021 ◽  
Vol 11 (2) ◽  
pp. 551
Author(s):  
Petros-Panagis Filippatos ◽  
Nikolaos Kelaidis ◽  
Maria Vasilopoulou ◽  
Dimitris Davazoglou ◽  
Alexander Chroneos
Keyword(s):  
Electronic Properties ◽  
Tin Oxide ◽  
Density Functional ◽  
Structural Changes ◽  
High Dielectric Constant ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Optical And Electronic Properties ◽  
High Dielectric ◽  
Gap States

In the present study, we performed density functional theory calculations (DFT) to investigate structural changes and their impact on the electronic properties in halogen (F, Cl, Br, and I) doped tin oxide (SnO2). We performed calculations for atoms intercalated either at interstitial or substitutional positions and then calculated the electronic structure and the optical properties of the doped SnO2. In all cases, a reduction in the bandgap value was evident, while gap states were also formed. Furthermore, when we insert these dopants in interstitial and substitutional positions, they all constitute a single acceptor and donor, respectively. This can also be seen in the density of states through the formation of gap states just above the valence band or below the conduction band, respectively. These gap states may contribute to significant changes in the optical and electronic properties of SnO2, thus affecting the metal oxide’s suitability for photovoltaics and photocatalytic devices. In particular, we found that iodine (I) doping of SnO2 induces a high dielectric constant while also reducing the oxide’s bandgap, making it more efficient for light-harvesting applications.

Geometric, electronic properties of Au$_l$Pt$_m$ ($l$+$m$$\leqslant$10) clusters: A first-principles study

2021 ◽  
Author(s):  
Wei-Feng Xie ◽  
Hao-Ran Zhu ◽  
Shi-Hao Wei
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
First Principles ◽  
Density Functional ◽  
Inverse Design ◽  
Functional Theory ◽  
First Principles Study

The structural evolutions and electronic properties of Au$_l$Pt$_m$ ($l$+$m$$\leqslant$10) clusters are investigated by using the first$-$principles methods based on density functional theory (DFT). We use Inverse design of materials by...

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