•The Blue-P/Al2SO vdW heterostructure has been predicted using first-principles calculations.•The Blue-P/Al2SO vdW heterostructure can facilitate the separation of photo-excited electrons and ...holes.•The CB and VB edges cover the standard redox potentials required for water splitting at 1≤pH≤10.•High optical absorption in the visible region for Blue-P/Al2SO vdW heterostructure compared to the individual monolayers.•The present Blue-P/Al2SO vdW heterostructure show optimal photovolatics and photocatalytic performance.
The enhancement of photocatalytic efficiency in monolayer materials receives a substantial boost through the deliberate construction of two-dimensional van der Waals heterostructures. In this work, we introduce a novel two-dimensional Blue-P/Al2SO vdW heterostructure through rigorous first principles calculations. Blue-P/Al2SO forms a type-II heterostructure with an indirect band gap of 1.64 eV (PBE) and 2.35 eV (HSE), and exhibits a large relative ratio (D), which arises from the effective separation of photogenerated electron-hole pairs and preventing their recombination . We have confirmed its dynamic and thermal stability by analyzing the phonon spectrum and conducting ab-initio molecular dynamics simulations at room temperature. The interface generates a built-in electric field that expedites the reorganization of photo-generated holes within Blue-P monolayer and photo-generated electrons within Al2SO monolayer. Crucially, the band edges of this heterostructure covers the water redox potential in a wide range of pH from acidic to basic solution, this provides a positive outlook for experiments aimed at preparing it as a photocatalyst. Furthermore, our investigations reveal that the light-absorption ability of the Blue-P/Al2SO vdW heterostructure is relatively strong. The highest light absorption peak is 3 × 105 cm−1 at 600 nm wavelength. Consequently, this newly designed Blue-P/Al2SO vdW heterostructure exhibits significant potential for applications in solar energy conversion and serves as a promising photocatalyst for facilitating the process of water splitting.
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In this paper we have studied the stability, mobility and voltage profile of alkali metal intercalated BC3 monolayer (MxBC3), for 0 < x ≤ 1 and M = Li, Na. Firstly, our calculations have the ...objective to identify the lower energy of Li and Na adsorption sites by using the density functional theory, then we calculate the minor diffusion energies of Na and Li on the surface of BC3 monolayer as shown by the total density of states of MxBC3 (M = Li, Na). Moreover, we showed that BC3 monolayer has changed his semiconductor character to metallic character after the adsorption of Li and Na on his surface. Importantly, we have demonstrated that BC3 monolayer has a higher theoretical capacity (582,63 mA h/g) as compared to Mo2C, VS2, MoS2, and graphite. Finally, we show that monolayer BC3 has a low average open-circuit voltage of 0.48 V for Li and 0.79 V for Na. These results highlight suggest that BC3 monolayer can be a promising anode material both for lithium-ion and sodium-ion batteries.
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•Li/NaBC3 monolayer has changed his semiconductor character to metallic character.•Na adsorbed configurations are more stable than the case of Li in general.•The capacities of Li2BC3 and Na2BC3 are 14102.79 mA h/g and 9227.13 mA h/g.•The diffusion energy of Li/Na, suggesting fast charging/discharging processes.•LixBC3 and NaxBC3 have small variation of voltage.
Using first-principles calculations based on density functional theory (DFT), the structural, optoelectronic, and transport properties of the MgICl Janus monolayer have been investigated. The ...stability is validated by the ab-initio molecular dynamics (AIMD), cohesive energy, and phonon spectrum. We found that Janus MgICl monolayer is a direct band-gap semiconductor with an energy gap of 3.35 eV (PBE) and 4.87 eV (HSE), and is energetic and dynamically stable. The dielectric matrix has been calculated within the random phase approximation (RPA). The optical-absorption coefficient is found to be very less in the visible region, and the calculated refractive index values are very near to that of water. The reflectivity is found to be less than 10% in the visible region which further increases in the UV region. The electrical conductivity of the Janus MgICl using Boltzmann transport theory, and the effective mass of electrons and holes have been calculated; the results present good electrical conductivity and small values of effective mass owing to high mobility. These theoretical investigations suggest that the Janus MgICl is a thermodynamically stable and promising material for use in the solar cells as a transparent conductor material.
Graphical Abstract
Arsenene, a single-layer arsenic nanosheet with a honeycomb structure, has recently attracted increasing attention due to its numerous exceptional properties. In this study, density functional theory ...(DFT) calculations were employed to investigate and compare the interactions of Li, Na and Mg ions with the Arsenene monolayer for the purpose of using it as an anode in lithium, sodium, and magnesium ion rechargeable batteries. The results indicated that the Li, Na and Mg adatoms preferentially adsorbed on the valley sites, with negative adsorption energies of −2.55, −1.91 and −1.10 eV, respectively. This strong binding between the alkali metals and the Arsenene monolayer is an important factor for battery applications. Also, it was found that Arsenene exhibited high theoretical specific capacities of up to 1430 mA h g
−1
for Li and Mg and 1073.18 mA h g
−1
for Na, which are extremely higher values than those of commercially used graphite anodes (372 mA h g
−1
) in Li-ion batteries. Furthermore, the diffusion barrier energies of the Li, Na and Mg ions were calculated using the nudged elastic band method. The activation energy barriers of these ions showed isotropic behavior for the different pathways (
X
,
Y
, and diagonal directions), where the obtained values were 0.16, 0.05 and 0.016 eV for Li, Na, and Mg ions, respectively. Our findings indicate that the high capacity, low open circuit voltage, and ultrahigh barrier diffusion make Arsenene a good candidate for application as an anode material for rechargeable batteries.
Arsenene, a single-layer arsenic nanosheet with a honeycomb structure, has recently attracted increasing attention due to its numerous exceptional properties.
We investigated the effect of the orientation of the cation MA (i.e., CH3NH3) on exciton’s mobility in the hybrid material MAPbI3 using the density functional theory. We calculated the effect of such ...an orientation on the lattice parameters, band structure, density of states, and electric conductivity. The latter was calculated using the Boltzmann transport equation in the relaxation time approximation as a function of the chemical potential. It is compared with the conductivity of the centrosymmetric material CsPbI3 to highlight the role played by MA in MAPbI3. Particularly, the conductivity in the latter is anisotropic, showing a pronounced enhancement along the direction of the dipolar moment of MA. Applications could take advantage of this result if they are made in a polarized phase. Our findings agree with experimental data for MAPbI3 under the effect of an external electric field.
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•Investigation of the electric conductivity in the Hybrid perovskite materials MAPbI3.•Effect of the rotation of the organic cation MA on the physical properties of MAPbI3.•Use of the Boltzmann equation in the relaxation time approximation for the electric conductivity.
Blue phosphorene (Blu-Pn) is a new phosphorene allotrope capable of hosting a substantial amount of sodium (Na) atoms. However, it has been reported to exhibit low electrical conductivity, chemical ...sensitivity, and structural stability, thus limiting its utility as an anode material for Na-ion batteries (NIBs). In this work, we introduce BC2N as a protective layer for Blu-Pn. Based on van der Waals (vdW) corrected density functional theory (DFT), we conduct a comprehensive first-principles study to explore the main electrochemical properties of the BC2N/Blu-Pn vdW heterostructure. The BC2N/Blu-Pn system exhibits a small band-gap of 0.03 eV that fades away and indicates metallic behavior upon Na adsorption. Furthermore, the binding energy of Na incorporated into the inter-layer of the BC2N/Blu-Pn system is lower (−2.03 eV) compared with those of free-standing BC2N (−1.25 eV) and Blu-Pn monolayer (−1.52 eV). Therefore, the growth of Na dendrites can be avoided. Furthermore, the migration energy barrier for the BC2N/Blu-Pn system is about 0.11 eV, indicating fast Na diffusion and excellent rate performance. Moreover, the theoretical storage capacity is 763 mA h g−1. Finally, we show that the intercalation of Na in the BC2N/Blu-Pn system has the advantage of a small average voltage of approximately 0.24 V. Besides these properties, the proposed heterostructure is based on chemical elements that are widely available and technologically established and have low atomic mass, which are all advantages for Na-ion battery applications.
2D materials beyond graphene and in particular 2D semiconductors have raised interest due to their unprecedented electronic properties, such as high carrier mobility or tunable bandgap. Blue ...phosphorene is an allotrope of black phosphorene that resembles graphene as it presents a honeycomb structure. However, it is known to have semiconductor character and the crucial point is to determine whether this hexagonal phase of phosphorene presents Dirac fermions as in graphene. Here, the first compelling experimental evidence of Dirac fermions in blue phosphorene layer grown on Cu(111) surface is presented. The results highlight the formation of a highly ordered blue phosphorene sheet with a clear Dirac cone at the high symmetry points of the Brillouin Zone. The charge carriers behave as massless relativistic particles. Therefore, all the expectations held for graphene, such as high‐speed electronic devices based on ballistic transport at room temperature, may also be applied to blue phosphorene.
Blue phosphorene is a new emerging 2D semiconducting material with potential applications. Herein, an evidence of the existence of Dirac fermions in blue phosphorene grown on Cu(111) substrate, similar to graphene, is presented. Therefore, all the expectations held for graphene, such as high‐speed electronic devices based on ballistic transport at room temperature, may also be applied to blue phosphorene.
In this study, we use density functional theory with the generalized gradient approximation proposed by Perdew–Burke–Ernzerhof (GGA-PBE) to investigate the effect of Al-doping on the structural, ...electronic and optical properties of the pyrite FeS
2
structure. It shows an indirect band gap of 1.07 eV, which is in reasonable agreement with the experimental data. When Al atom occupies the Fe site, one of the most effects occurred in the electronic structure is to create shallow donor states partially occupied at the bottom of the conduction band, which could be considered as the primary induced origin of the electrical conductivity in the Al doped FeS
2
system. Then, the injection of free electrons into the conduction band could be carried out only from the low excitation energies as well as the photon absorptions could be enhanced in the visible range. Therefore, all these features may be making of Al-doped FeS
2
a useful material for cell photovoltaic applications with a reasonable cost.
In recent years, search for applicable bidimensional (2D) hydrogen storage materials with high capacity and excellent H
2
physisorption properties has attracted considerable attention from scientists ...and researchers. According to the rational design, and using first-principles calculations, we propose a t-graphene-like boron nitride monolayer (t-B
4
N
4
) for hydrogen storage application by replacing C atoms in t-graphene with B and N atoms. The thermal stability and polarization mechanisms of lithium atoms adsorbed at the center of octagons on the t-B
4
N
4
system were evaluated at 300 K using
ab initio
molecular dynamics (AIMD) calculations. Moreover, Li-decorated double-sided t-B
4
N
4
can store up to 32H
2
molecules with an average hydrogen adsorption energy of 0.217 eV per H
2
and a maximum hydrogen storage capacity of 12.47 wt%. The reversibility of adsorbed hydrogen was checked and the calculated desorption temperature was 161 K, much higher than the critical point for hydrogen. Based on diffusion barriers, the H
2
molecule diffusion kinetics is faster on the t-B
4
N
4
surface than that on t-graphene and graphene.
Lithium decoration enhances the hydrogen storage capacities, reversibility and diffusion kinetics of t-boron nitride monolayer.
Using first-principles calculations based on density functional theory (DFT), the structural, optical and electronic properties of antimonene, phosphorene and their binary compound have been ...systematically investigated. The dielectric matrix has been calculated within the random phase approximation (RPA). We have calculated the dielectric function and absorption coefficient. Our simulations show that these materials can exhibit anisotropic optoelectronic properties, high spin-orbit coupling (SOC) especially for antimonene and Buckled-SbP compound while for phosphorene and Puckered-PSb compound the spin-orbit coupling is observed to be minor. The optical activity of Buckled-SbP compound cover a wide range between 1.6 and 9 eV(138–775 nm, UV and Visible regions), which is longer than that of antimonene, phosphorene and Puckered-PSb compound. This offer possibilities towards applications as 2D materials in solar cells as an absorber 2D materials, light-emitting devices and photodetectors.
