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The effects of tensile and compressive deformation on the structural stability, electronic structure and optical properties of the Zn atom-adsorbed borophene system, which are exhibited by reflectivity, absorption coefficient, bandgap and adsorption energy, were studied using the first-principles calculations based on density functional theory (DFT). The borophene planes were found to be distorted following Zn atom adsorption. The adsorption energy calculations show that the stability decreases both under tensile and compressive strains. When tensile and compressive loading increase to 5%, respectively, the system loses the stability and the ability of adsorbing Zn atoms on borophene. The band structure and density of states analysis show that the band structure of borophene is changed by the Zn atom adsorption, with a band overlap near the Fermi level and more impurity energy levels in the conduction band. The hybridization is formed between Zn atom and borophene in the range of –12 eV to 6 eV, with the s and p orbitals both contributing to the conduction and valence bands, but p orbitals make a larger contribution to the total density of states than s orbitals. Studies of optical properties have shown that tensile and compressive strains both increase the dielectric constant of the adsorbed system, with compressive strains causing a redshift in the major peaks of the real and imaginary parts of the spectrum. The tensile strain has little effect on the absorption coefficient and reflectance of the borophene. As the compressive strain increases, the peak absorption coefficient of the adsorbed system is shifted to the blue and the peak reflectance is redshifted. [ABSTRACT FROM AUTHOR]

The effect of biaxial strain on O-doped monolayers MoS2 has been systematically studied by the first-principles calculations. It is shown that the strain decreases the structural stability of O-doped monolayer MoS2. Between 0% and 12% tensile strains, the bandgap steadily narrows. At different compression strains, the bandgap increases and then decreases. The optical properties analysis shows that the strain causes the peaks of both the real and imaginary parts of the dielectric function to appear in the low energy region. And it affects the absorption and reflection peaks of the doping system so that it has a strong absorption of photons in the ultraviolet region. The doping system shows resonance in the range of 0–10 eV. The results of this study verify that strain can properly regulate the electronic and optical properties of O-doped monolayer MoS2, and provide a theoretical reference for the implementation of MoS2 in optoelectronic devices. [ABSTRACT FROM AUTHOR]

With the development of industrialization, the use of mercury in industry has become more and more widespread, causing serious impacts on the environment. It is therefore urgent to find new effective ways to combat mercury pollution. In this paper, The effect of C, O, P, Ni and Au doping on the adsorption of Hg atoms by WS 2 has been investigated based on the first nature principle of density functional theory. The electronic structures and optical properties of the adsorbed systems were calculated after atomic doping. The results show that the absolute value of the adsorption energy of the intrinsic adsorption system is small and does not favour the adsorption of Hg on WS 2. However, after C, P, Ni and Au doping, the adsorption energy of the system is significantly increased and a strong charge transfer between WS 2 and Hg atoms occurs, as well as a significant change in the band gap of the structure. This suggests that atomic doping favors the adsorption of Hg by WS 2. The effect of O doping on the adsorption system is not significant. In addition, a study of the optical properties revealed that the static dielectric constants of the system appeared to increase to varying degrees after the doping of the atoms. The doping of P, Ni and Au atoms increases the light absorption coefficient and contributes to the photocatalytic efficiency of the structures. The doped atoms cause a red shift in the reflectivity peak of the adsorbed system. In summary, the doping of C, P, Ni and Au enhances the adsorption of Hg atoms on WS 2. O doping has less effect on the adsorption of Hg on WS 2. • In this paper, the effect of C, O, P, Ni and Au doping on the adsorption of Hg atoms by WS2 was investigated. • The results show that atomic doping favors the adsorption of Hg by WS2. • Atomic doping alters the electronic properties of the structure. • Atomic doping alters the optical properties of the structure. [ABSTRACT FROM AUTHOR]

The electronic and optical properties of hydrogenated silicene at different torsion angles are investigated using the density functional theory (DFT). It was found that when silicene was hydrogenated, the Si atoms were pulled out of plane due to covalent interactions between the Si and H atoms, increasing their flexural height to 0.731 Å. Torsional deformation decreases the structural stability of hydrogenated silicene and its adsorption energy decreases with increasing twist angle. Under the effect of torsion deformation, the bandgap of hydrogenated silicene increases and then decreases. The bandgap is 2.168 eV at a torsion angle of 0∘, indicating a wide bandgap semiconductor. Mulliken's charge population analysis shows that charge transfer occurs between Si–H atoms, with Si atoms losing electrons and becoming positively charged and H atoms gaining electrons and becoming negatively charged. From the analysis of optical properties, the torsional deformation induced the maximum absorption and reflection peaks of all the hydrogenated silicene systems to appear in the ultraviolet region. Compared with the system without torsional deformation, these peaks exhibit varying degrees of red and blue shifts. The above findings provide guidance for the application of silicene in nanooptoelectronic devices. [ABSTRACT FROM AUTHOR]

• Shear deformation reduces the structural stability of the doped system. The forbidden band width of the doped system decreases sequentially with increasing shear deformation, while conductivity increases. • The density of states of both intrinsic and doped systems is primarily contributed by the 4d and 3p orbitals of the Mo and S atoms, respectively. • Analysis of the optical properties reveals that shear deformation enhances the static permittivity of the doped systems, leading to an increased ability to bind charges. • Compared to the doped system without shear deformation, absorption peaks of the remaining doped systems shift towards the high energy region, resulting in enhanced utilization of ultraviolet light. The effect of O-atom doping on the electronic and optical properties of monolayer MoS 2 under shear deformation has been systematically investigated using first principles. The results show that shear deformation reduces the structural stability of the doped system. The forbidden band width of the doped system decreases sequentially with increasing shear deformation, while conductivity increases. The density of states of both intrinsic and doped systems is primarily contributed by the 4d and 3p orbitals of the Mo and S atoms, respectively. Analysis of the optical properties reveals that shear deformation enhances the static permittivity of the doped systems, leading to an increased ability to bind charges. Additionally, absorption and reflection peaks of all doped systems occur in the ultraviolet region. Compared to the doped system without shear deformation, absorption peaks of the remaining doped systems shift towards the high energy region, resulting in enhanced utilization of ultraviolet light. In the energy range of 16.7–17.3 eV, peak energy loss of all doped systems decreases sequentially, suggesting that shear deformation can reduce energy loss. These results demonstrate that shear deformation can modulate the optoelectronic properties of O-doped monolayer MoS 2 and provide a theoretical foundation for practical applications in semiconductor devices. Variation of band gap values of intrinsic and O-doped monolayer MoS 2 under different shear deformation [Display omitted] [ABSTRACT FROM AUTHOR]

First-principles research has been used to carefully examine the structural stability of the architecture, electronic structure, and optical characteristics of monolayer WS2-doped Mo atoms during shear deformation. Calculations show that the required formation energy gradually increases when shear deformation is increased from 2% to 8%, the bandgap of the system decreases from 1.732eV to 0.922eV, and the static dielectric function increases from 2.59 to 2.74. The absorption peaks are maximum for all doped systems between 11.5eV and 12.5eV. The peak absorption of the deformed system is redshifted compared to the original doped system. With increasing shear deformation, the peak energy loss of the system shows a decrease followed by an increase. [ABSTRACT FROM AUTHOR]