Graphene nanoribbons (GNRs) can be mainly classified into armchair graphene nanoribbons (aGNRs) and zigzag graphene nanoribbons (zGNRs) by different edge chiral directions. In this work, by introducing Stone-Wales defects on the edges of the V-shaped aGNRs, we propose a kind of armchair/zigzag edge hybridized GNRs (a/zHGNRs) and using the density functional theory and the nonequilibrium Green's function method, the band structures and electronic transport properties of the a/zHGNRs have been calculated. Our results show that an indirect bandgap appears in the band structures of the a/zHGNRs, which is very different from the direct bandgap of aGNRs and gapless of zGNRs. We also find that the valance band is mainly derived from the armchair partial atoms on the hybridized edge, while the conduction band comes mainly from the zigzag partial atoms of the hybridized edge. Meanwhile, the bandgap also oscillates with a period of three when the ribbon width increases. In addition, our quantum transport calculations show that there is a remarkable transition between the semiconductor and the metal with different ribbon widths in the a/zHGNRs devices, and the corresponding physical analysis is given.

Abstract Atomically precise open‐shell graphene fragments, such as extended peri ‐acenes, hold significant interest for electronics and spintronics. However, their inherent high reactivity poses challenges for synthesis and application. In this study, a novel approach is introduced: the fusion of a zigzag‐edged peri ‐tetracene with an all‐armchair‐edged hexa‐ peri ‐hexabenzocoronene (HBC) via two shared benzene rings to produce a stable open‐shell hydrocarbon, named dibenzo‐ peri ‐heptacene (DBPH). The DBPH derivative 1 exhibits considerably enhanced stability, with a half‐life ( t 1/2 ) of 46 days in toluene solution under ambient conditions. This improved stability is attributed to peri ‐benzannulation, enhanced aromatic stabilization, and kinetic protection of the reactive sites along the zigzag edges. The structure of 1 is unequivocally verified through single‐crystal X‐ray diffraction analysis. With a balanced combination of armchair and zigzag edge structures, derivative 1 displays a diradical character of 39.2% and a singlet‐triplet gap of ≈−3.16 kcal mol −1 . It features a narrow electrochemical energy gap (0.87 eV) and exhibits amphoteric redox behavior. Notably, its dication and dianion states manifest a closed‐shell singlet ground state, representing doubly charged structures where a HBC unit is fused with a benzo[ f ]tetraphene moiety. This research paves the way for synthesizing novel open‐shell graphene fragments with adjustable electronic properties and exceptional stability.

Well-studied cycloparaphenylenes (CPPs) correspond to the simplest segments of armchair CNTs, whereas the corresponding macrocyclic oligophenylene strip of zigzag CNTs is still missing. Herein, we present two series of conjugated macrocycles (CM2PP and CN2PP) containing two <i>meta</i>-phenylene or 2,7-naphthylene units facing each other in the strip. CM2PP and CN2PP can be regarded as the shortest cyclic primitive segments of zigzag CNTs. They were synthesized by gold-mediated dimerization and unambiguously characterized. They adopted the tubular structures and can further pack into one-dimensional supramolecular nanotubes. In particular, the supramolecular nanotube of CM2P4P mimics the CNT(9, 0) structure. Structural analysis and theoretical calculation accounted for the reduced ring strain in CM2PPs and CN2PPs. CM2PPs and CN2PPs exhibited a large optical extinction coefficient and high photoluminescence quantum yield. CN2P8P can accommodate fullerene C₆₀, forming a Saturn-like C₆₀@CN2P8P complex, a mimic structure of zigzag CNT peapods.

A three-dimensional finite element (FE) model for single-walled carbon nanotubes with armchair and zigzag shapes is proposed in this paper (SWCNTs). Nodes are positioned at the locations of carbon atoms to design the FE models. And three-dimensional elastic beam components are used to model the bonds between them. The effect of the diameter length/diameter ratio on the diameter length/diameter ratio, cross sectional aspect ratio and number of elements on the Young’s modulus of SWCNTs has been considered herein. From the conducted experiments it can be observed that, the larger tube diameter can lead to higher Young’s modulus for carbon nanotubes. Such that, maximum elastic modulus for the armchair and the zigzag models has been obtained to be 1.0285TPa and 1.0396TPa when the diameters for the armchair and the zigzag models were 2.034nm and 1.957nm respectively. Increasing the length/diameter ratio has led the Young’s modulus to be increased for armchair and zigzag models such that its values can reach 1.0451TPa and 1.0191TPa respectively. The cross sectional aspect ratio of SWCNTs showed an inversely proportional effect on the elastic modulus in this work. As a result of rising the cross sectional aspect ratio to be2, the Young's modulus for armchair and zigzag models has decreased to 0.7991TPa and 0.8873TPa, accordingly. The change in geometry has been observed to be a defect and it is in general can decrease the modulus of elasticity. The number of elements in the armchair model considered as prominent factor that increases the young’s modulus to be 1.0280TPa when the number of element is 10836. In zigzag model, the number of element has no effect on the elastic modulus since the number of nodes that exposed to the applied load is fixed in this case. The findings showed that the proposed FE model may be useful for studying carbon nanotube mechanical action in the future.

A single-wall carbon nanotube can be viewed as a one-dimensional material created by rolling up a sheet of graphene. Its electronic band structure depends on the chirality, i.e., how the sheet has been rolled up, yet synthesizing the symmetry at will is rather challenging. We structure an artificial honeycomb lattice in both a zigzag and an armchair tube and explore their topological features for sound. Our findings reveal how armchair tubes remain gapless, whereas the zigzag counterparts host nontrivial edge states of non-zero quantized Zak phase, which are dictated by the circumferential number of units. Unlike man-made planar lattices whose underling symmetry must be broken to harvest quantum Hall and pseudospin phases, interestingly, the structured tubular lattice symmetry remains intact, while its nontrivial phase alone is governed by the chirality and the tube diameter. We foresee that our results, not only for sound, but also in photonics, mechanics and electronics will broaden future avenues for fundamental and applied sciences.

Graphene quantum dots (GQDs) are known as promising zero-dimensional nanomaterials due to their tunable electronic and optical properties arising from quantum confinement and edge effects. In this work, a comprehensive density functional theory investigation is carried out to explore the influence of semi-metal doping and edge configuration on the structural, electronic, chemical reactivity, and optical properties of hexagonal graphene quantum dots. Two edge types, zigzag and armchair, are considered for pristine GQDs and GQDs doped with fourth group (Si, Ge) and fifth group elements (As, Sb). All geometries are fully optimized using the CAM-B3LYP and ωB97XD functionals via DFT, and the electronic excitations are analyzed via time-dependent density functional theory (TD-DFT). The results exhibit that heteroatom doping induces significant structural distortion due to the larger covalent radii of dopants and their specific valence shell electron configuration compared to carbon. Electronic structure analysis shows that both dopant type and edge configuration strongly modulate the HOMO–LUMO gap and density of states. In particular, doping the GQDs with fourth group elements —especially with zigzag edges—exhibit a pronounced reduction in bandgap, chemical hardness, and an enhancement in dipole moment and electrophilicity index, indicating improved charge-transfer capability and electronic reactivity. In contrast, arsenic- and antimony-doped systems introduce more localized electronic states, higher electrophilicity, and increased structural strain, because of their different valence shell electron configuration compared with carbon, suggesting carrier trapping tendencies that are less favorable for electronic transport applications.

Graphene quantum dots (GQDs) are known as promising zero-dimensional nanomaterials due to their tunable electronic and optical properties arising from quantum confinement and edge effects. In this work, a comprehensive density functional theory investigation is carried out to explore the influence of semi-metal doping and edge configuration on the structural, electronic, chemical reactivity, and optical properties of hexagonal graphene quantum dots. Two edge types, zigzag and armchair, are considered for pristine GQDs and GQDs doped with fourth group (Si, Ge) and fifth group elements (As, Sb). All geometries are fully optimized using the CAM-B3LYP and ωB97XD functionals via DFT, and the electronic excitations are analyzed via time-dependent density functional theory (TD-DFT). The results exhibit that heteroatom doping induces significant structural distortion due to the larger covalent radii of dopants and their specific valence shell electron configuration compared to carbon. Electronic structure analysis shows that both dopant type and edge configuration strongly modulate the HOMO–LUMO gap and density of states. In particular, doping the GQDs with fourth group elements —especially with zigzag edges—exhibit a pronounced reduction in bandgap, chemical hardness, and an enhancement in dipole moment and electrophilicity index, indicating improved charge-transfer capability and electronic reactivity. In contrast, arsenic- and antimony-doped systems introduce more localized electronic states, higher electrophilicity, and increased structural strain, because of their different valence shell electron configuration compared with carbon, suggesting carrier trapping tendencies that are less favorable for electronic transport applications.

Chemically realistic quasi-one-dimensional (1D) materials in which Dirac Fermions and highly degenerate flat bands coexist intrinsically at the Fermi level are exceedingly rare, while representing a highly desirable platform for correlated and topological quantum phenomena. Here, in this work, using specialized symmetry-adapted first-principles calculations we predict a new class of nanomaterials─phosphorus carbide nanotubes (P 2 C 3 NTs)─obtained by rolling monolayer P 2 C 3 , a two-dimensional material shown in a previous letter to host “double Kagome bands”. Both armchair and zigzag P 2 C 3 NTs are stable at room temperature and feature the rare coexistence of Dirac crossings and multiple flat bands at the Fermi level inherited from the underlying honeycomb–Kagome lattice, with the flat bands resilient to elastic deformations. Under large strain, the structure transforms from honeycomb–Kagome to “brick-wall”, accompanied by multiple coupled structural and quantum phase transitions. We also uncover localized edge states, spin splitting from vacancies and dopants, and strain-tunable magnetism. Together, these results establish P 2 C 3 NTs as a chemically specific and mechanically tunable 1D material platform with potential applications in quantum hardware and spintronics.