The discovery of GRAPHENE and its remarkable electronic and magnetic properties has initiated great research interest in this material. Furthermore, there are many derivatives in these GRAPHENE related materials among which GRAPHENE NANORIBBONS and GRAPHENE nanofragments are candidates for future carbon-based nanoelectronics and spintronics. Theoretical studies have shown that magnetism can arise in various situations such as point defects, disorder and reduced dimensionality. Using a mean field Hubbard model, we studied the appearance of magnetic textures in zero-dimensional GRAPHENE nanofragments and one-dimensional GRAPHENE zigzag NANORIBBONS. Among nanofragments, triangular shape, bowtie and coronene were studied. We explain how the shape of these materials, the imbalance in the number of atoms belonging to the GRAPHENE sublattices, the existence of zero-energy states and the total and local magnetic moments were related. At the end, we focused on the effects of a model disorder potential (Anderson-type), and illustrate how density of states of zigzag NANORIBBONS was affected.

We report the enhanced capacitance of the Multi-Walled Carbon NanoTubes (MWCNTs) after a chemical unzipping process in concentrated sulfuric acid (H2SO4) and potassium permanganate (KMnO4). The effects of the test duration and temperature were investigated on the unzipping process of the MWCNTs to synthesize the GRAPHENE oxide NANORIBBONS. The SEM and TEM studies were carried out on untreated and unzipped MWCNTs samples to investigate the cutting and unzipping of the MWCNTs. The results confirmed that the efficient tube unzipping with improved effective surface area was obtained from the 1h treatment at 60oC, at which most of the tubes were opened without any tube annihilation. The graphite plate deposited with the untreated and unzipped MWCNTs samples was investigated by electrochemical studies. Cyclic voltammetry studies showed that the MWCNTs after 1h unzipping at 60°C had better electrochemical behavior than the other samples. Galvanostatic charging/discharging measurements were carried out on the untreated and unzipped MWCNTs samples. A remarkable specific capacitance of 33 Fg-1 was obtained for the unzipped MWCNTs at a current density of 1 Ag-1 in 0.5 M KCl solution compared with 8 Fg-1 for pristine MWCNTs, again confirming the enhanced effective surface area and increased defect density in the tube surfaces after the unzipping process. These results make the unzipped MWCNTs a promising electrode material for all energy storage applications.

This research explores how two-dimensional honeycomb materials can be used in advanced electronics, focusing on zigzag honeycomb NANORIBBONS. These NANORIBBONS can create zero-energy band gaps, enabling helical spin current edge states. The study investigates the quantum spin Hall state, showcasing the adaptability of the Kane-Mele model in various honeycomb lattices. In addition to the theoretical discussions, this study presents a detailed Hamiltonian, performs band structure computations, and introduces a novel spin-filtering technique for zigzag NANORIBBONS. This method enhances our understanding of edge-localized quantum states and can revolutionize spintronics. By revealing the quantum states in honeycomb NANORIBBONS, this study contributes to the advancement of electronics and offers a promising path for highly efficient spin-based technologies.

In this paper, we study the electronic conductance of the flat and bent armchair and zigzag GRAPHENE NANORIBBONS in the presence and absence of an external magnetic field within the nearest neighbor tight-binding approach. For the armchair case, we reduce the Hamiltonian of each benzene ring including the treated magnetic flux to the Hamiltonian of a two atomic molecule by using the renormalization method. Also, consider the effect of magnetic field by inserting the flux dependent phase coefficients in the corresponding hopping energies in the problem. Finally, we perform the numerical calculations related to the transmission coefficient by the means of the Green’s function technique within the Landauer approach. The results show that the applying an external magnetic field on the armchair nanoribbon creates some extra gaps in the conductance spectra. The widths of these gaps depend on the amount of nanoribbon bending. Furthermore, the value of conductance in the central gap for armchair case is more sensitive on the bending and magnetic field amounts with respect to zigzag case.

The structural and electronic properties of the hydrogenated porous GRAPHENE NANORIBBONS were studied by using density functional theory calculations. The results show that the hydrogenated porous GRAPHENE NANORIBBONS are energetically stable. The effects of ribbon type and ribbon width on the electronic properties of these NANORIBBONS were investigated. It was found that both armchair and zigzag hydrogenated porous GRAPHENE NANORIBBONS are semiconductors. Their energy band gaps depend on the ribbon width and topological shape of carbon atoms at the edges of the NANORIBBONS. The band gap of the NANORIBBONS decreases monotonically with increasing the ribbon width. The semiconducting properties of the hydrogenated porous GRAPHENE NANORIBBONS suggest these ribbons as proper materials for use in future nanoelectronic devices.

In this paper, the electronic properties of AGNRs defected by quantum antidots is studied. The defected AGNRs are modeled by imposing linear, diagonal, triangle, hexagonal and symmetric, and asymmetric rhomboid arrays of antidots in the middle of pristine NANORIBBONS which lead to antidot super-lattice of AGNRs. It can be realized that the quantum confinement of NANORIBBONS is quite changed by the presence of defects. This quantum confinement results in novel electronic properties like the band structure, and transmission function. It can be realized that two critical factors play important roles in changing the electronic properties of ASiNRs defected by quantum antidot arrays: The first one is the number of atoms extracted, and the other one is the symmetric or asymmetric arrays of the defects. Our results indicate that in the band structure of NANORIBBONS defected by quantum antidots, the flat bands have been created in the band structure of the system, so the degenerate electronic states and the accessible states increased too. Symmetrical quantum antidot arrays have closer electronic properties to pristine ASiNRs. Therefore, by selecting the number of extracted atoms, as well as the symmetry or asymmetry of the shape, the electronic properties of the system can be changed. In addition, the electronic properties of NANORIBBONS are investigated by the distance between two adjacent antidots(d). Finally, one can extracted that the electronic properties of armchair GRAPHENE NANORIBBONS can be tuned by changing dimensional parameters. Numerical tight-binding model, coupled with the non-equilibrium Green’, s function formalism are applied to extract the electronic properties of NANORIBBONS.

In this article, the electronic, structural and magnetic properties of hydrogenated GRAPHENE NANORIBBONS with zigzag-shaped edges (ZGNR-H) and armchair-shaped edges (AGNR-H) have been investigated using density functional theory (DFT). The spin density of states and band structure have been calculated for ZGNR-H and AGNR-H NANORIBBONS with different widths. The results show that the electronic and magnetic properties of GRAPHENE NANORIBBONS are strongly dependent on the width of the ribbon and the shape of the edge of the ribbon, which is zigzag or armchair. So that the hydrogenated armchair ribbons are all non-magnetic semiconductors and with the increase in the width of the ribbon, there is a periodic and decreasing bandgap trend. While zigzag hydrogenated GRAPHENE NANORIBBONS with different widths are all magnetic metal and the values of magnetic moment for ZGNR-H NANORIBBONS increase with increasing of ribbon widths.

A complete inspectation on the free vibration of bilayer GRAPHENE NANORIBBONS (BLGNRs) modeled as sandwich beams considered tensile-compressive, and shear effects of van der Waals (vdWs) interactions between adjacent GRAPHENE NANORIBBONS (GNRs) as well as between GNRs and polymer matrix is performed in this research. In this modeling, nanoribbon layers play the role of sandwich beam layers and are modeled based upon the Euler-Bernoulli theory. In order to deliberate effects of vdWs interactions between adjacent GNRs as well as between GNRs and polymer matrix, their equivalent tensile-compressive and shear moduli are contemplated and applied in derivation of governing equations instead of employing conventional Winkler and Pasternak effects for elastic medium. The governing equations of motion are derived by considering the assumptions and employing sandwich beam theory, and natural frequencies are acquired by implementing harmonic differential quadrature method (HDQM). A detailed study is performed to examine the influences of the tensile-compressive and shear effects of vdWs interactions between adjacent GNRs as well as between GNRs and polymer matrix on the free vibration of BLGNRs.