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Graphdiyne and derivatives with delocalized π-electron systems are of particular interest owing to their structural, electronic, and transport properties, which are important for potential applications in next-generation electronics. Inspired by recently obtained extended graphdiyne nanowires, explorations of the modulation of the band gap and carrier mobility of this new species are still needed before application in device fabrication. To provide a deeper understanding of these issues, herein we present theoretical studies of one-dimensional extended graphdiyne nanowires using first-principle calculations. Modulation of the electronic properties of the extended graphdiyne nanowire was investigated systemically by considering several chemical and physical factors, including electric field, chemical functionalization, and carbo-merization. The band gap was observed to increase upon application of an electric field parallel to the plane of the synthesized graphdiyne nanowire in a non-periodic direction. Although chemical functionalization and carbo-merization caused the band gaps to decrease, the semiconducting property of the nanowires was preserved. Band gap engineering of the extended graphdiyne nanowires was explored regarding the field strength and the number of −C≡C− units in the carbon chain fragments. The charge carrier mobility of chemically functionalized and carbo-merized extended graphdiyne nanowires was also calculated to provide a comparison with pristine nanowire. Moreover, crystal orbital analysis was performed in order to discern the electronic and charge transport properties of the extended graphdiyne nanowires modified by the aforementioned chemical and physical factors. [ABSTRACT FROM AUTHOR]

Abstract: Structure and electronic properties of zigzag single-walled carbon nanotubes with multi-dichlorocarbene addition are investigated using self-consistent field crystal orbital method. It is found that the addition can cause large deformation of the tubes and significantly modify the band structures. The addition can even cause semiconductor–metal phase transition. Furthermore, the mobility and conductivity are also calculated using the deformation potential approach for the addition systems. [Copyright &y& Elsevier]

Abstract: Theoretical studies are presented on carbon nanowires (CNWs) made of linear carbon chains encapsulated inside armchair carbon nanotubes with various tube diameters. The structural and electronic properties as well as bonding features were investigated systematically by using ab initio self-consistent-field crystal orbital method based on density functional theory. The interaction between the tube and the chain becomes more obvious as the diameter of the CNW decreases and even weaker chemical bonds are formed between the tube and the chain in the smallest CNWs. The comparison of the elastic moduli between CNWs and CNTs supports that the mechanically unstable carbon chain is indeed protected by the CNT shell upon the encapsulation. All the CNWs we calculated are metals with zero band gaps. The encapsulation of the carbon chain may modulate the electronic properties for the CNWs depending on the tube size and the filling density of carbon atoms. [Copyright &y& Elsevier]

Abstract: This article presents ab initio self-consistent-field crystal orbital calculations on the structural and electronic properties for recently-discovered carbon nanowires (CNWs) made of linear carbon chains inserted inside zigzag carbon nanotubes using density functional theory. The studies focus on the change of geometric structures and electronic properties upon the encapsulation. It is found that the carbon nanotubes can stabilize the encapsulated carbon chain which prefers a dimerized structure in the tube with larger diameters. The interaction between the tube and the chain becomes more obvious when the tube size decreases, leading to the change of structures and the energy bands upon encapsulation. All the CNWs we calculated are metals with zero band gap. The encapsulation of the carbon chain may modulate the electronic properties for the CNWs depending on the tube size and the filling density of carbon atoms. Therefore, it is expected that CNWs’s electronic properties can be controlled artificially by filling carbon chains with various densities of atoms into the nanotubes. [Copyright &y& Elsevier]

Abstract: The total carbo-mer of single-walled carbon nanotubes (C-SWCNTs) are constructed by inserting two sp carbon atoms into each C–C bond in pristine single-walled carbon nanotubes (SWCNTs). The geometric, mechanical and electronic properties for these novel structures are investigated by self-consistent-field crystal calculations. The calculated zigzag and chiral C-SWCNTs are all small gap semiconductors, whereas the metallic property is still kept in the armchair C-SWCNT. The calculated Young''s moduli of C-SWCNTs are smaller than those of SWCNTs. Our calculations show that the zigzag C-SWCNTs have higher mobility than the corresponding SWCNTs. Moreover, the calculated mobility of the C-SWCNTs has a periodic change with the change of the tube diameters. [Copyright &y& Elsevier]

This article presents first-principles self-consistent-field crystal orbital calculations on the structures and electronic properties for the combined systems made of nitrogen atom chains inserted in zigzag carbon nanotubes (CNTs). We find that the nitrogen chains with the zigzag structure can be well stabilized by the outside CNTs. The molecular dynamics simulations based on density functional with tight binding method confirmed the stability of nitrogen chains under the confined conditions. Thus the zigzag CNTs can be as containers to confine and stabilize the polymeric nitrogen chains. According to the obtained binding energy, (9, 0) tube is the most favorable to filling the nitrogen chain. The combined systems are all metals except the filling into (7, 0) tube, indicating the encapsulation of the nitrogen chain can modulate the electronic properties for the combined systems. The interaction between the nitrogen chain and CNTs is also discussed based on the reduced density gradient, band structures and electronic density difference analysis. It is found that the van der Waals force, charge transfer and orbital interaction are all important for the formation of the combined systems. [ABSTRACT FROM AUTHOR]

The structure stabilities and electronic properties are investigated by using ab initio self-consistent-field crystal orbital method based on density functional theory for the one-dimensional (1D) double-wall nanotubes made of n -gon SiO 2 nanotubes encapsulated inside zigzag carbon nanotubes. It is found that formation of the combined systems is energetically favorable when the distance between the two constituents is around the Van der Waals scope. The obtained band structures show that all the combined systems are semiconductors with nonzero energy gaps. The frontier energy bands (the highest occupied band and the lowest unoccupied band) of double-wall nanotubes are mainly derived from the corresponding carbon nanotubes. The mobilities of charge carriers are calculated to be within the range of 10 2 –10 4 cm 2 V −1 s −1 for the hybrid double-wall nanotubes. Young’s moduli are also calculated for the combined systems. For the comparison, geometrical and electronic properties of n -gon SiO 2 nanotubes are also calculated and discussed. [ABSTRACT FROM AUTHOR]

Abstract: The structure–property relationship of the nanopeapods—one dimensional (1D) C60O polymer encapsulated in single-walled carbon nanotubes (SWCNTs)—is studied by means of the self-consistent field crystal orbital method. The calculations show that the nearest distance between the two constituents is within Van der Waals interaction scope in the most stable two peapods. The SWCNT sizes affect not only the stability but also the electronic structures of the peapods. The peapods with larger tube diameters keep the semiconductive and metallic properties of the corresponding pristine SWCNTs. These combination systems are stiffer than the corresponding SWCNTs due to larger Young''s moduli. The magnitude order of the calculated mobility of charge carriers is in the range of 102–105 cm2 V−1 s−1 for the peapods, indicating that the combined systems may be good high-mobility electronic materials. [Copyright &y& Elsevier]

Abstract: The tetrathiafulvalene (TTF) functionalized armchair single-walled carbon nanotube (SWCNT) is investigated using self-consistent-field crystal orbital calculations based on the density functional theory. The studies focus on the structure and electronic properties upon the functionalization of the SWCNT by TTF molecule. Our calculations show that the external absorption of TTF is less stable than the encapsulated ones. It is found that the metallic character of the SWCNT remains for all the models are considered here. Additionally, we also calculated the charge carrier mobility for the one-dimensional (1D) TTF@SWCNT chain with deformational potential approach. [Copyright &y& Elsevier]