Density-functional theory (DFT) was applied to investigate the geometry and electronic properties of bare Si60 and H-terminated Si-fullerene. DFT predicts outward sites on a bare Si60 cage. By using π-orbital axis analysis (POAV), it is shown that these sites result from a strong tendency of silicon atoms to form sp(3) hybridization bonds. Natural bond orbital (NBO) analysis confirms the sp(3) hybridization nature of Si-Si bonds in Si-fulleranes. The quantum confinement effect (QCE) does not affect band gap (BG) so strongly in the size between 1 and 1.7 nm. In contrast, the geometry and symmetry of the cage have a significant influence on the BG. In contrast to their carbon analogs, pentagon rings increase the stability of the cages. Functionalized Si-cages are stable and can be chemically very active. The electronic properties are highly sensitive to the surface chemistry via functionalization with different chemical groups. As a result, BGs and chemical activities of these cages can be drastically tuned through the chemistry of the surface.

We investigate the electronic response of single-walled carbon nanotubes (SWCNTs) and a carbon nanobelt (CNB) to N-linked and O-linked SARS-CoV-2 spike glycoproteins, using ab initio quantum mechanical approach. The CNTs are selected from three zigzag, armchair, and chiral groups. We examine the effect of carbon nanotube (CNT) chirality on the interaction between CNTs and glycoproteins. Results indicate that the chiral semiconductor CNTs clearly response to the presence of the glycoproteins by changing the electronic band gaps and electron density of states (DOS). Since the changes in the CNTs band gaps in the presence of N-linked are about two times larger than the changes in the presence of the O-linked glycoprotein, chiral CNT may distinguish different types of the glycoproteins. The same results are obtained from CNBs. Thereby, we predict CNBs and chiral CNTs have suitable potential in sequential analysis of N- and O-linked glycosylation of the spike protein.

In this study, we first obtain the single-band tight-binding parameters of a B7 cluster in terms of matching the HOMO–LUMO levels obtained from density functional theory (DFT).

In this study, based on density functional theory, we propose a new branch of pseudo-fullerenes which contain triple bonds with sp hybridization. We call these new nanostructures fullerynes, according to IUPAC. We present four samples with the chemical formula of C4nHn, and the structures derived from fulleranes. We compare the structural and electronic properties of these structures with those of two common fullerenes and fulleranes systems. The calculated electron affinities of the sampled fullerynes are negative, and much smaller than those of fullerenes, so they should be chemically more stable than fullerenes. Although fulleranes also exhibit higher chemical stability than fullerynes, but pentagon or hexagon of the fullerane structures cannot pass ions and molecules. Applications of fullerynes can be included in the storage of ions and gases at the nanoscale. On the other hand, they can also be used as cathode/anode electrodes in lithium-ion batteries.

In this paper, we introduce new features of silicon in fullerane structures. Silicon, when placed in a fullerane structure, increases its electron affinity and electrophilicity index, compared to placement in a diamondoids structure. These nanoparticles can be used to make optical sensors to detect viral environments. In this work, we theoretically examine the changes in the UV-Visible spectrum of sila-fulleranes by interacting with viral spikes. As a result, we find out how the color of silicon nanoparticles changes when they interact with viruses. We apply N- and O-Links for viral glycoprotein structures, and Si20H20 silicon dodecahedrane, respectively. Our computational method to obtain optimal structures and their energy in the ground and excited states, is density functional theory (DFT). Besides, to get the UV-Visible spectrum, time-dependent density functional theory (TD-DFT) approach has been used. Our results show that the color of sila-dodecahedrane is white, and turns green in the face of viral spikes. We can use the optical sensitivity of silicon nanoparticles, especially to identify environments infected with the novel coronavirus.