| 1. |
- Bahti, Soukaina, et al.
(författare)
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Structures, stabilities, optoelectronic and photocatalytic properties of Janus aluminium mono-chalcogenides Al(Ga, In)STe monolayers
- 2022
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Ingår i: Physica. E, Low-Dimensional systems and nanostructures. - : Elsevier. - 1386-9477 .- 1873-1759. ; 142
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Tidskriftsartikel (refereegranskat)abstract
- Computational design of new two-dimensional materials constitutes an effective and promising approach in the development and exploration of a wide range of emerging applications such as optoelectronics, photocatalysis, energy storage, and conversion. Within the framework of this work, we systematically investigated for the first time, the structural, stability, optoelectronic, and pho-tocatalytic properties of new predicted Al(Ga, In)STe monolayers derived from Janus Aluminium mono-chalcogenides through Density Functional Theory and Ab-Initio molecular dynamic simulations. After a full optimization of both struc-tures, their dynamics and thermal stability was confirmed through the calculations of phonon spectrum and ab-initio molecular dynamics at a chosen temperature, respectively. Subsequently, the electronic and optical properties were explored and findings revealed that both monolayers exhibit a semiconducting characteristic with a direct and indirect electronic band gap of about 2.23 and 2.69 eV using HSE06 hybrid functional for AlGaSTe and AlInSTe monolayers, re-spectively. Furthermore, the optical absorption indicates a strong absorption of light in the range between 3 and 18 eV. More noticeably, Both Janus monolayers considered exhibiting a promising optical absorption in the visible wavelength region with an absorption coefficient greater than 105 cm−1. In addition, the photocatalytic properties of these structures were investigated by plotting the band edge positions straddle the reduction potential of H2 and the oxidation potential H2O. Based on our results, we conclude that both monolayers offer good thermodynamic stability allowing them to be processed experimentally and can be used as very appropriate candidates for optoelectronics and photocatalytic applications.
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| 2. |
- Bouhou, Samira, et al.
(författare)
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A Theoretical Study of Hysteresis Behaviors of 2D Mixed Spin-(1/2,1)Ising Nanopaticles
- 2018
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Ingår i: 2018 6th International Renewable And Sustainable Energy Conference (IRSEC). - : IEEE. - 9781728111827 ; , s. 194-198
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Konferensbidrag (refereegranskat)abstract
- The EffectiveField Theory with correlations (EFT) based on the probability distribution is used to investigate the magnetic hysteresis behaviors of both hexagonal and square 2D nanoparticles consisting of a ferromagnetic spin-1/2 core and a ferromagnetic spin-1 shell. The system parameters such as the ferrimagnetic exchange core/shell interaction, the surface shell exchange coupling and the reduced temperatureare examined on the magnetic hysteresis behaviors. Some interesting results have been found such as multiple hysteresis loop behaviors.
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| 3. |
- Bouziani, Ilyas, et al.
(författare)
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Computational prediction of two-dimensional o-Al2N2 under applied strain for boosting the photocatalytic hydrogen evolution reaction performance
- 2023
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Ingår i: International journal of hydrogen energy. - : Elsevier. - 0360-3199 .- 1879-3487. ; 48:91, s. 35542-35551
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Tidskriftsartikel (refereegranskat)abstract
- Photocatalytic water splitting for clean hydrogen fuel production provides a promising approach to solve the energy and environmental issues. Recently, two-dimensional (2D) photocatalysts have attracted growing interest owing to their short carrier diffusion path, abundant active sites and large surface area. This study explores the photocatalytic performance of 2D orthorhombic dialuminum dinitride (o-Al2N2) using density functional theory. The computational results show that the o-Al2N2 monolayer has a semiconductor character with indirect and moderate bandgap. Moreover, this system exhibits high light absorption in the visible region, referring to its high capacity for harvesting sunlight. Meanwhile, under neutral pH, the band edge positions are suitable to straddle water redox potentials and the hydrogen evolution reaction is energetically favorable to allow hydrogen production on the surface of 2D o-Al2N2 compound. More importantly, the photocatalytic activity of o-Al2N2 monolayer is significantly improved under slight biaxial compressive strain. Therefore, our findings suggest that the o-Al2N2 nanomaterial is a highly efficient 2D photocatalyst for hydrogen production via water splitting under neutral pH.(c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
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| 4. |
- Bouziani, I, et al.
(författare)
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Electronic and optical properties of ZnO nanosheet doped and codoped with Be and/or Mg for ultraviolet optoelectronic technologies : density functional calculations
- 2020
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Ingår i: Physica Scripta. - : IOP PUBLISHING LTD. - 0031-8949 .- 1402-4896. ; 95:1
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Tidskriftsartikel (refereegranskat)abstract
- Theoretically, the density functional calculations have been effectuated for investigating electronic and optical properties of zinc oxide nanosheet doped and codoped with Be and/or Mg utilizing the generalized gradient approximation modified Becke-Johnson (GGA-mBJ) approach. The computed results show that the ZnBeO, ZnMgO and ZnBeMgO in nanosheet structure, referring to their low formation energy values, are more stable than those in bulk one. Furthermore, the bandgap of ZnO monolayer can be effectively modulated through substitution of Zn atoms by Be and/or Mg. In addition to that, by incorporating Be and/or Mg, the absorption peaks of ZnO nanosheet shift into the shorter UV-wavelength side as well as its reflectivity becomes lower. These results indicate that doping and codoping process of ZnO monolayer with Be and/or Mg are two efficient ways to modulate electronic and optical properties for ultraviolet optoelectronic technologies.
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| 5. |
- Bouziani, Ilyas, et al.
(författare)
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Janus Ga2SeTe and In2SeTe nanosheets : Excellent photocatalysts for hydrogen production under neutral pH
- 2023
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Ingår i: International journal of hydrogen energy. - : Elsevier. - 0360-3199 .- 1879-3487. ; 48:43, s. 16358-16369
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Tidskriftsartikel (refereegranskat)abstract
- In the past few years, Janus nanosheets have attracted much interest according to their specific structure and considerable potential to address the energy and environmental issues. Herein, the electronic, optical and photocatalytic properties of two-dimensional Janus Ga2SeTe and In2SeTe have been studied using ab-initio computations based on the density functional theory. The obtained results show that these nanomaterials exhibit a semiconductor behavior with direct and moderate bandgaps using hybrid HSE06 func-tional. Subsequently, the understudied compounds present suitable optical conductivity, absorption, transmission and reflectivity for water splitting under the ultraviolet-visible light irradiation. Interestingly, the band edge positions of Janus Ga2SeTe and In2SeTe excellently straddle the redox potentials of water under neutral pH. Additionally, the free energy values for the formation of H2 from H adsorbed on the Ga2SeTe and In2SeTe com-pounds are respectively 1.304eV and 0.976eV at pH = 7. More excitingly, the present study proposes strain engineering approach to improve the photocatalytic performance of the Janus Ga2SeTe and In2SeTe monolayers. Specifically, the investigated semiconductors show more appropriate band edge alignment and better hydrogen evolution reaction ac-tivity under biaxial tensile strain, which fulfil the water splitting requirements at neutral pH conditions. Our findings conclude that the Janus Ga2SeTe and In2SeTe nanosheets are promising candidates for photocatalytic hydrogen production.
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| 6. |
- Haman, Zakaryae, et al.
(författare)
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Computational identification of efficient 2D Aluminium chalcogenides monolayers for optoelectronics and photocatalysts applications
- 2021
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 556
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Tidskriftsartikel (refereegranskat)abstract
- The massive consumption of traditional fossil fuel like oil, coal and natural gas has led to serious environmental issues, which drove the search for cleaner renewable energy sources. One such option is photocatalytic water splitting that has attracted much attention as a viable process for the large scale production of hydrogen as a renewable fuel. Within this perspective, we methodically studied the structural, optoelectronic, and photocatalytic properties of two-dimensional aluminum monochalcogenide monolayers with the chemical formula AlX (X = O, S, Se, and Te) based on the framework of Density Functional Theory (DFT). All considered structures are full relaxed and their thermodynamic stabilities are confirmed by computing the phonon spectrum and Ab Initio Molecular Dynamics (AIMD) simulations. The electronic characteristics are also performed on the basis of both exchange correlation functional GGA-PBE and HSE06 in order to obtain the accurate electronic band gap. According to our calculations, all the four monolayers posses indirect band gaps ranging between 1.937 and 2.46 eV. Furthermore, based on desirable electronic band gaps, the optical performance features were further explored including complex refractive index, absorption coefficient and energy loss function by means of the complex dielectric function. It is found that all the four materials present a high absorption coefficient in the visible and Ultra-Violet regions. Finally, the band edge positions of our monolayers straddle the reduction potential of H2 and the oxidation potential H2O. Also, it was found that the Gibbs free energy of 2D AlO monolayer is 0.02 eV at certain applied external electric field and very close to ideal catalysts which suggest that the AlO monolayer is better candidate for hydrogen production. Our findings demonstrate that AlX monolayers are suitable materials for optoelectronics and hydrogen production via photocatalytic water splitting.
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| 7. |
- Haman, Zakaryae, et al.
(författare)
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Janus Aluminum Oxysulfide Al2OS : A promising 2D direct semiconductor photocatalyst with strong visible light harvesting
- 2022
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Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 589
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Tidskriftsartikel (refereegranskat)abstract
- Hydrogen production via solar light-driven water dissociation has been regarded as an artificial and effective process to overcome the environmental problem as well as solving the current energy crisis. In this regard, numerous works have mainly been devoted to developing the appropriate photocatalyst which satisfies the conditions for water splitting and understanding the photocatalysis process. In this study, we propose for the first time the potential application of the two-dimensional Janus aluminum oxysulfide Al2OS as an efficient photocatalyst material for hydrogen-production H-2 through the first-principles calculations. Janus Al2OS monolayer has been designed from the parental binary aluminum sulfide AlS by substituting one sub-layer of sulfide atoms (S) to oxygen atoms (O). The electronic properties of the pristine AlS and the derived Janus Al2OS were computed using GGA-PBE and HSE06 functionals. According to the band structure, AlS monolayer shows a semiconductor behavior with an indirect bandgap of 2.14 eV whereas, the Janus Al2OS exhibits a direct bandgap of 1.579 eV. Motivated by the desirable bandgap of the Janus Al2OS, the absorption-coefficient of Janus Al2OS shows strong visible light harvesting compared to the parental AlS. Furthermore, the photocatalytic performance of Al2OS has been investigated. Our calculations demonstrate that the band edge position of Al2OS is suitable for the hydrogen evolution reaction (HER). More importantly, based on the reaction coordinate, it was found that the Gibbs free-energy Delta G(H*) of Al2OS is 0.97 eV which is smaller than of the two-dimensional Janus Ga2XY (X, Y = S, Se, Te with X not equal Y) reported recently. Moreover, this value decreases from 0.97 eV to 0.69 eV under 0.5 V/angstrom of an external electrical field. Our results indicate that Janus Al2OS fulfills the fundamental requirements for efficient photo-catalyst under visible light and provides new guidance for hydrogen-production via water splitting.
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| 8. |
- Haman, Zakaryae, et al.
(författare)
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Photocatalytic and thermoelectric performance of asymmetrical two-dimensional Janus aluminum chalcogenides
- 2023
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Ingår i: Journal of Physics. - : IOP Publishing. - 2515-7655. ; 5:3
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Tidskriftsartikel (refereegranskat)abstract
- Through a density functional theory-driven survey, a comprehensive investigation of two-dimensional (2D) Janus aluminum-based monochalcogenides (Al2XY with X/Y = S, Se, and Te) has been performed within this study. To begin with, it is established that the examined phase, in which the Al-atoms are located at the two inner planes while the (S, Se, and Te)-atoms occupy the two outer planes in the unit cell, are energetically, mechanically, dynamically, and thermally stable. To address the electronic and optical properties, the hybrid function HSE06 has been employed. It is at first revealed that all three monolayers display a semiconducting nature with an indirect band gap ranging from 1.82 to 2.79 eV with a refractive index greater than 1.5, which implies that they would be transparent materials. Furthermore, the monolayers feature strong absorption spectra of around 10(5) cm(-1) within the visible and ultraviolet regions, suggesting their potential use in optoelectronic devices. Concerning the photocatalytic performance, the conduction band-edge positions straddle the hydrogen evolution reaction redox level. Also, it is observed that the computed Gibbs free energy is around 1.15 eV, which is lower and comparable to some recently reported 2D-based Janus monolayers. Additionally, the thermoelectric properties are further investigated and found to offer a large thermal power as well as a high figure of merit (ZT) around 1.03. The aforementioned results strongly suggest that the 2D Janus Al-based monochalcogenide exhibits suitable characteristics as a potential material for high-performance optoelectronic and thermoelectric applications.
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| 9. |
- Khossossi, Nabil, et al.
(författare)
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Ab initio study of a 2D h-BAs monolayer : a promising anode material for alkali-metal ion batteries
- 2019
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : ROYAL SOC CHEMISTRY. - 1463-9076 .- 1463-9084. ; 21:33, s. 18328-18337
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Tidskriftsartikel (refereegranskat)abstract
- The selection of a suitable two dimensional anode material is one of the key steps in the development of alkali metal ion batteries to achieve superior performance with an ultrahigh rate of charging/discharging capability. Here, we have used state of the art density functional theory (DFT) to explore the feasibility of two dimensional (2D) honeycomb boron arsenide (h-BAs) as a potential anode for alkali-metal (Li/Na/K)-ion batteries. The structural and dynamic stability has been confirmed from the formation energy and the non-negative phonon frequency. The h-BAs monolayer exhibits negative adsorption-energy values of -0.422, -0.321 and -0.814 eV, for the Li, Na, and K-ions, respectively. Subsequently, during the charging process the adsorption-energy increases considerably without an energy-barrier when any of the A-atoms achieve a crucial distance (similar to 8 angstrom). In addition, it has been observed that insertion of the mono alkali metal atom into the h-BAs surface results in the semi-conducting nature of the monolayer being transformed into a metallic-state. The low energy barriers for Li (0.522 eV), Na (0.248), and K (0.204 eV) active ion migration imply high diffusion over the h-BAs surface, hence suggesting it has a high charge/discharge capability. Moreover, we have obtained low average operating voltages of 0.49 V (Li), 0.35 V (Na) and 0.26 V (K) and high theoretical capacities of 522.08 mA h g(-1) (for Li and Na) and 209.46 mA h g(-1) (for K) in this study. The aforementioned findings indicate that a h-BAs monolayer could be a promising anode material in the search for low cost and high performance alkali metal ion batteries.
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| 10. |
- Khossossi, Nabil, et al.
(författare)
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High-Specific-Capacity and High-Performing Post-Lithium-Ion Battery Anode over 2D Black Arsenic Phosphorus
- 2021
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Ingår i: ACS Applied Energy Materials. - : American Chemical Society (ACS). - 2574-0962. ; 4:8, s. 7900-7910
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Tidskriftsartikel (refereegranskat)abstract
- Nowadays, secondary batteries based on sodium (Na), potassium (K), and magnesium (Mg) stimulate curiosity as eventually high-availability, nontoxic, and eco-friendly alternatives of lithium-ion batteries (LIBs). Against this background, a spate of studies has been carried out over the past few years on anode materials suitable for post-lithium-ion battery (PLIBs), in particular sodium-, potassium- and magnesium-ion batteries. Here, we have consistently studied the efficiency of a 2D alpha-phase arsenic phosphorus (alpha-AsP) as anodes through density functional theory (DFT) basin-hopping Monte Carlo algorithm (BHMC) and ab initio molecular dynamics (AIMD) calculations. Our findings show that alpha-AsP is an optimal anode material with very high stabilities, high binding strength, intrinsic metallic characteristic after (Na/K/Mg) adsorption, theoretical specific capacity, and ultralow ion diffusion barriers. The ultralow energy barriers are found to be 0.066 eV (Na), 0.043 eV (K), and 0.058 eV (Mg), inferior to that of the widely investigated MXene materials. During the charging process, a wide (Na+/K+/Mg2+) concentration storage from which a high specific capacity of 759.24/506.16/253.08 mAh/g for Na/K/Mg ions was achieved with average operating voltages of 0.84, 0.93, and 0.52 V, respectively. The above results provide valuable insights for the experimental setup of outstanding anode material for post-Li-ion battery.
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