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Silicon-based two-dimensional (2D) materials have garnered significant attention due to their unique properties and potential applications in electronics, optoelectronics, and other advanced technologies. Here, we present a comprehensive investigation of a novel silicon allotrope, Popsilicene (Pop-Si), derived from the structure of Popgraphene. Using density functional theory and ab initio molecular dynamics simulations, we explore the thermal stability, mechanical and electronic properties, and optical characteristics of Pop-Si. Our results demonstrate that Pop-Si exhibits good thermal stability at 1000 K. Electronic structure calculations reveal that Pop-Si is metallic, with a high density of states at the Fermi level. Furthermore, our analysis of the optical properties indicates that Pop-Si has pronounced UV-Vis optical activity, making it a promising candidate for optoelectronic devices. Mechanical property assessments show that Pop-Si has Young's modulus ranging from 10 to 92 GPa and a Poisson's ratio of 0.95. These results combined suggest its potential for practical applications.
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CONTEXT: Popgraphene (PopG) is a two-dimensional carbon-based material with fused pentagonal and octagonal rings. Like graphene, it exhibits a metallic band gap and exceptional thermal, dynamic, and mechanical stability. Here, we theoretically study the electronic and structural properties of PopG monolayers, including their doped and vacancy-endowed versions, as O[Formula: see text] adsorbers. Our findings show that pristine and vacancy-endowed PopG sheets have a comparable ability to adsorb O[Formula: see text] molecules, with adsorption energies ranging from [Formula: see text]0.57 to [Formula: see text]0.59 eV (physisorption). In these cases, octagonal rings play a dominant role in the adsorption mechanism. Platinum and Silicon doping enhance the O[Formula: see text] adsorption in areas close to the octagonal rings, resulting in adsorption energies ranging from [Formula: see text]1.13 to [Formula: see text]2.56 eV (chemisorption). Furthermore, we computed the recovery time for the adsorbed O[Formula: see text] molecules. The results suggest that PopG/O[Formula: see text] interaction in pristine and vacancy-endowed cases can change the PopG electronic properties before O[Formula: see text] diffusion. METHODS: Density Functional Theory (DFT) simulations, with Van der Waals corrections (DFT-D, within the Grimme scheme), were performed to study the structural and electronic properties of PopG/O[Formula: see text] systems using the DMol3 code within the Biovia Materials Studio software. The exchange and correlation functions are treated within the generalized gradient approximation (GGA) as parameterized by Perdew-Burke-Ernzerhof (PBE) functional. We used the double-zeta plus polarization (DZP) for the basis set in these cases. We also considered the BSSE correction through the counterpoise method and the nuclei-valence electron interactions by including semi-core DFT pseudopotentials.
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Carbon-based tubular materials have sparked a great interest in future electronics and optoelectronics device applications. In this work, we computationally studied the mechanical properties of nanotubes generated from popgraphene (PopNTs). Popgraphene is a 2D carbon allotrope composed of 5-8-5 rings. We carried out fully atomistic reactive (ReaxFF) molecular dynamics for PopNTs of different chiralities ( n,0 and 0,n ) and/or diameters and at different temperatures (from 300 up to 1200â K). Results showed that the tubes are thermally stable (at least up to 1200â K). All tubes presented stress/strain curves with a quasi-linear behavior followed by an abrupt drop of stress values. Interestingly, armchair-like PopNTs ( 0,n ) can stand a higher strain load before fracturing when contrasted to the zigzag-like ones ( n,0 ). Moreover, it was obtained that Young's modulus (YMod ) (750-900â GPa) and ultimate strength (σUS ) (120-150â GPa) values are similar to the ones reported for conventional armchair and zigzag carbon nanotubes. YMod values obtained for PopNTs are not significantly temperature-dependent. While the σUS values for the 0,n showed a quasi-linear dependence with the temperature, the n,0 exhibited no clear trends.
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Popgraphene (PopG) is a new 2D planar carbon allotrope which is composed of 5-8-5 carbon rings. PopG is intrinsically metallic and possesses excellent thermal and mechanical stability. In this work, we report a detailed study of the thermal effects on the mechanical properties of PopG membranes using fully-atomistic reactive (ReaxFF) molecular dynamics simulations. Our results showed that PopG presents very distinct fracture mechanisms depending on the temperature and direction of the applied stretching. The main fracture dynamics trends are temperature independent and exhibit an abrupt rupture followed by fast crack propagation. The reason for this anisotropy is due to the fact that y-direction stretching leads to a deformation in the shape of the rings that cause the breaking of bonds in the pentagon-octagon and pentagon-pentagon ring connections, which is not observed for the x-direction. PopG is less stiff than graphene membranes, but the Young's modulus value is only 15 % smaller.