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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]

In the present paper, the effect of different bent angles on structural stability, electronic structure, and optical properties of Na absorbed borophene system is investigated using the density functional theory. The structure of the borophene was almost unchanged and the planar structure was not disrupted after the adsorption of a Na atom. Directly above the bottom B–B bonds is considered as the optimal adsorption position of single. The stability of the Na adsorbed borophene system can be decreased under the condition of different bent angles. The adsorption of Na atoms changes the energy band structure of the intrinsic borophene according to the calculation results of energy band structure and density of states, which resulting the conduction band contains more impurities. The 2p orbital of Na and the 3p orbital of B hybridize between −4 eV and 6 eV. Bending deformation gives rise to the electron transfer between Na atoms and B atoms. In terms of optical properties, the bending deformation improves the absorption of infrared light and the catalytic activity of light in the adsorbed system. • The structure of the borophene was almost unchanged and the planar structure was not disrupted after the adsorption of a Na atom. • The stability of the Na adsorbed borophene system can be decreased under the condition of different bent angles. • The adsorption of Na atoms changes the energy band structure of the intrinsic borophene so that its conduction band contains more impurities. • The bending deformation improves the absorption of infrared light and the catalytic activity of light in the adsorbed system. [ABSTRACT FROM AUTHOR]