The electronic and structural properties of molecular and solid cubane have been studied by first-principles, self-consistent field total energy calculations. Calculated molecular properties such as equilibrium geometry and electronic and vibrational spectra are found to be in good agreement with experimental data. Structural parameters and the energetics of both the low-temperature, orientationally ordered and high-temperature, orientationally disordered or plastic phases of solid cubane are determined. The valence band of solid cubane is derived from the molecular states; the energy gap between the lowest unoccupied and highest occupied molecular orbital bands is rather large due to the saturated carbon atoms. The effect of alkali-metal-atom doping on the electronic energy bands is investigated. It is found that the metallic band of doped cubane is derived from the undoped solid cubane’s lowest conduction band with a significant contribution from the alkali-metal atom.

Solid-state argyrodite electrolytes are promising candidate materials to produce safe all-solid-state lithium batteries (ASSLBs) due to their high ionic conductivity. These batteries can be used to power electric vehicles and portable consumer electronics which need high power density. Atomic-scale modeling with ab initio calculations became an invaluable tool to better understand the intrinsic properties and stability of these materials. It is also used to create new structures to tailor their properties. This review article presents some of the recent theoretical investigations based on atomic-scale modeling to study argyrodite electrolytes for ASSLBs. A comparison of the effectiveness of argyrodite materials used for ASSLBs and the underlying advantages and disadvantages of the argyrodite materials are also presented in this article.

Recent experiments showed that there are very strong adhesion forces between nanotubes and surfaces. These forces are much stronger than the adhesion forces of gecko's foot hairs on substrates. Thus, nanotubes become candidates to be used in dry adhesives. Here, we present theoretical investigations on the adhesion between nanotubes and graphite surfaces. Molecular dynamics simulations and energy minimisation calculations were performed. Layer-by-layer deformations of the nanotube tips were observed. Parallel and perpendicular components of the forces were calculated for different contact angles of nanotubes. Adhesion forces are found to be maximised at 15° impact angles of nanotubes with respect to surface normal.

Recently, nanoporous graphene has attracted great interest in the scientific community. It possesses nano-sized holes; thus, it has a highly accessible surface area for lithium adsorption for energy storage applications. Defective graphene has been extensively studied. However, the lithium adsorption mechanism of nanoporous graphene is not clearly understood yet. Here, we present theoretical investigations on the lithium-ion adsorption mechanism in nanoporous graphene. We perform ab initio electronic structure calculations based on density functional theory. Lithium adsorption in a graphene nanopore is studied and adsorption sites are determined. We also study different lithium-ion distributions in graphene nanopores to determine the best lithium–nanoporous graphene structures for lithium-ion batteries. We show that lithium ions can be adsorbed in a graphene nanopore, even in a single layer of graphene. It is also shown that adding more nanopores to multilayer nanoporous graphene can result in higher Li storage capacity for new-generation lithium-ion batteries.

We find stiffness properties of van der Waals heterostructures made of graphene and carbon nanotubes (CNTs) using molecular dynamics (MD) simulations. The variation of the stiffness tensor is studied at different temperatures for structures with changing CNT density, and orientations. Orthotropic structures with unidirectional CNTs have high stiffness ∼300–500 GPa, in one direction. Structures with transverse isotropy show stiffness of ∼150–350 GPa along two mutually perpendicular directions. The orthotropic structures also show greater stiffness with increasing CNT density, while the others are insensitive to it. In general,the stiffness constant values are decrease as temperatures increase. The results can aid in determining useful heterostructure configuration for a particular application and in finding overall stiffness of devices having additional components.

Recently, we showed that novel fullerene-porphyrin supramolecular nanowires are very promising structures to be used in organic photovoltaics and molecular electronics. These nanowires have clear channels for charge transport for electrons and holes, however, transparent conducting electrodes such as graphene are necessary for charge collection for solar cell operation. Here, we present theoretical investigations on fullerene-porphyrin dyad-graphene interactions for organic photovoltaics and molecular electronics. Atomic models of fullerene (C60), zinc-tetraphenylporphyrin (ZnTPP) and their dyad on a single layer graphene are created and their structural and electronic properties are studied using classical molecular mechanics and quantum ab-initio density functional theory calculations. Equilibrium structures are determined. Our studies show that the C60ZnTPP dyad and graphene interact more strongly than the individual C60 or ZNTPP molecules with graphene. It is also found that C60ZnTPP-graphene combined structure has metallic character with it has half-filled mixed electronic states at the Fermi level. Our investigations show that graphene is a promising electrode for organic photovoltaics and electronics involving C60ZnTPP.