Co-reporter:Bing Liang, Hongcun Bai, Yuanhe Huang
Computational and Theoretical Chemistry 2017 Volume 1115(Volume 1115) pp:
Publication Date(Web):1 September 2017
DOI:10.1016/j.comptc.2017.06.017
•The optimized one-dimensional BN-substituted graphyne NRs still keep plane structures.•The stabilities of these NRs decrease as their widths increase.•The band gap can be tuned by BN substituting, which enlarge band gap of the corresponding graphyne•The BN substituting modificates the charge carrier transport property of pure graphyne NRs.This paper presents the self-consistent field crystal orbital studies of the BN-substituted graphyne nanoribbons (NRs) based on density functional theory. Two kinds of the substitution are considered: one is that the six-membered rings in the graphyne NRs are replaced by the corresponding BN hexagonal rings; another is the substitution of acetylenic linkages by BN units. The calculations show that all the optimized one-dimensional BN-substituted graphyne NRs still keep plane structures. These NRs are semiconductors with non-zero band gaps and their band gaps are wider than those of corresponding graphyne NRs but narrower than those of BNNRs. The substitution of hexagonal rings leads to wider band gap than the substitution of acetylenic linkages. The relationship of band gaps with the ribbon widths is different from different NR patterns. The stabilities of these BN-substituted graphyne NRs monotonically decrease as their widths increase and the molecular dynamics simulations show that these NRs would be stable when T < 600 K. Natural population analysis shows that BN bonds have stronger ionicity in the hexagonal rings than in the BN linkages. The dependence of the charge carrier mobilities on the ribbon widths is also quite different from different types of the BN-substituted graphyne NRs. It is found that both the substituting types and edge structures have important influence on the transport property of the BN-substituted NRs. Thus, BN substituting indeed plays an important role in tuning the electronic structure of graphyne.Download high-res image (89KB)Download full-size image
Co-reporter:Ying Zhu;Dr. Hongcun Bai; Yuanhe Huang
ChemistryOpen 2016 Volume 5( Issue 1) pp:78-87
Publication Date(Web):
DOI:10.1002/open.201500154
Abstract
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.
Co-reporter:Yanli Sun, Hongcun Bai and Yuanhe Huang
RSC Advances 2015 vol. 5(Issue 12) pp:8965-8973
Publication Date(Web):22 Dec 2014
DOI:10.1039/C4RA10947C
In this study, one-dimensional (1D) graphdiyne-like BN (BN-diBN) nanoribbons (NRs) with armchair and zigzag edges are studied using the self-consistent field crystal orbital method based on the density functional theory. The structures, stabilities, electronic properties and charge carrier mobility of these NRs with different widths are investigated and compared to their isoelectronic equivalents, namely, the corresponding graphdiyne NRs. The formation of most of the BN-diBN NRs is energetically favorable according to the calculated Gibbs free energies. The stabilities of these BN-diBN NRs increase as their widths increase. The calculations show that the BN-diBN strips are all semiconductors with wide band gaps. The variation of the band gaps with respect to the NR widths is different for the two patterns of BN-diBN NRs. The mobilities of charge carriers for these BN-diBN NRs are calculated based on the deformation potential theory and effective mass approach. The mobilities are not the monotonic function of the NR widths and have different dependencies on the NR widths for BN-diBN NRs with different edge structures. It is found that the armchair and zigzag BN-diBN NRs are more favorable for the transportation of holes and electrons, respectively.
Co-reporter:Ying Zhu, Hongcun Bai, Yuanhe Huang
Synthetic Metals 2015 Volume 204() pp:57-64
Publication Date(Web):June 2015
DOI:10.1016/j.synthmet.2015.03.002
•The band gaps of the extended wires can be turned by the sizes and connections.•The 1D nanowires are good candidates of transport materials with high charge carrier mobility.•The electron has higher mobility than the hole due to the distinct crystal orbital distribution.This work presented theoretical studies on the extended nanowires constructed from narrow graphene nanoribbons and atomic carbon chains by using self-consistent field crystal orbital method based on density functional theory. The size and connection effects on geometrical structure, relative stability and electronic property of these one-dimensional (1D) nanowires have been addressed systemically and in details. It is found that the ratio of narrow graphene nanoribbons and CC units may be the key factor to the relative thermodynamic stability of these 1D wires based on the obtained Gibbs free energy. All the extended nanowires studied have a direct band gap according to the calculated electronic band structures. The obtained band gaps of the nanowires are in the range of 0.918–2.015 eV. These flexible band gaps imply the possibility to modulate the electronic properties of these extended wires by turning the sizes and connections. Furthermore, a quantitative relation between the band gap and the ratio of phenylene and CC units is obtained. Moreover, we calculate the charge carrier mobility of the extended nanowires based on the deformation potential theory and effective mass approach. The frontier crystal orbital analyses are performed to get a better understanding of the charge carrier mobility for the 1D nanowires with various sizes and connections.
Co-reporter:Weiye Qiao, Xinqian Li, Hongcun Bai, Ying Zhu, Yuanhe Huang
Journal of Solid State Chemistry 2012 Volume 186() pp:64-69
Publication Date(Web):February 2012
DOI:10.1016/j.jssc.2011.11.039
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.Graphical abstractFormation of the novel peapod—1D C60O polymer encapsulated inside single-walled carbon nanotube.Highlights► Several novel peapods encapsulating one dimensional C60O polymers are constructed. ► Interwall distance of the two most stable peapods is in the Van der Waals scope. ► All peapods studied are stiffer than the corresponding SWCNTs. ► These peapods have high mobilies—in the order of 102–105 cm2 V−1 s−1.
Co-reporter:Hongcun Bai, Weiye Qiao, Ying Zhu, Yuanhe Huang
Diamond and Related Materials 2012 Volume 26() pp:20-24
Publication Date(Web):June 2012
DOI:10.1016/j.diamond.2012.03.008
Several possible one-dimensional (1D) polymers constructed from fullerene D5h C50 cages are investigated by means of the self-consistent field crystal orbital method based on density functional theory. In this paper we focus on their structures, stabilities, and electronic and elastic properties. It is found that several factors, such as the bonding position, the connection pattern and the size of the reserved aromatic domains as well as the charge state contribute to the stabilities of these polymers. The calculated band structures show that these 1D polymers exhibit semiconducting or metallic properties in neutral case. As for the elastic property, these polymers are softer than the single-walled carbon nanotubes according to the calculated Young's moduli. We also calculated the anionic 1D polymers. Large density of state values at the Fermi level is found for the charged systems. The possibility of superconduction is also discussed based on the electron–phonon coupling mechanism.Highlights► The one-dimensional C50 polymers are investigated based on DFT calculations. ► The band structures show that C50 polymers can be a semiconductor or a metal. ► Several charged polymers exhibit large density of states at Fermi energy level. ► The possible superconduction of the polymers is discussed.
Co-reporter:Guo Wang, Yuanhe Huang
Chemical Physics 2012 Volume 406() pp:65-71
Publication Date(Web):8 October 2012
DOI:10.1016/j.chemphys.2012.08.004
Abstract
The combined systems of peanut-shaped carbon nanotubes encapsulated in both semiconducting and metallic single-walled carbon nanotubes are investigated by using self-consistent field crystal orbital method based on the density functional theory. The investigation indicates that the interaction between the two constituents is mainly contributed by the π orbitals. The encapsulation does not change the semiconducting or metallic nature of the single-walled carbon nanotubes, but significantly changes the band dispersion and decreases the frontier band width of the metallic one. The carrier mobility and mean free path of the metallic single-walled carbon nanotube increase greatly after the encapsulation. The calculated mobilities have the order of 103 cm2 V−1 s−1 for both of the semiconducting and metallic double-walled carbon nanotubes.
Co-reporter:Hongcun Bai, Ying Zhu, Weiye Qiao and Yuanhe Huang
RSC Advances 2011 vol. 1(Issue 5) pp:768-775
Publication Date(Web):06 Sep 2011
DOI:10.1039/C1RA00481F
The one-dimensional graphdiyne nanoribbons are studied using the self-consistent field crystal orbital method based on density functional theory in this paper. The structures, stabilities, electronic, elastic and transport properties of these nanoribbons with different edges and widths are investigated. These graphdiyne strips can be obtained from cutting the graphdiyne sheet or the carbomerization of the graphene strips. It is found that the carbomerization not only expands the structures, but also alters the stabilities, electronic, elastic and transport properties of the original systems. Here the graphdiyne nanoribbons studied are all more stable than the graphdiyne monolayer in the view of energy. Different from the graphene nanoribbons, the graphdiyne strips are all semiconductors. According to our calculations, the band gaps of the graphdiyne strips decrease monotonically as the widths increase. A quantitative relation between the band gaps and the widths of the graphdiyne nanoribbons is obtained. Moreover, we also calculate the mobilities of charge carriers for these strips based on the deformation potential theory and effective mass approach. The calculated mobilities are in the range of 102–106 cm2 V−1s−1 at room temperature. The relationship between mobilities and nanoribbon widths is different for electron and hole charge carriers. The mobilities of electrons are always larger than those of holes for these graphdiyne nanoribbons studied. Hence, the graphdiyne strips are possibly more favorable for electron transportation.
Co-reporter:Wei Liu, Yuxue Li, Yuanhe Huang
Journal of Physics and Chemistry of Solids 2011 Volume 72(Issue 4) pp:299-306
Publication Date(Web):April 2011
DOI:10.1016/j.jpcs.2011.02.002
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.Highlights► We model carbo-merization of single-walled carbon nanotubes (C-SWCNTs). ► We examine the stability, the mechanical and the electronic properties of these nanotubes. ► The calculated Young.'s moduli of C-SWCNTs are smaller than those of SWCNTs. ► The zigzag C-SWCNTs have higher mobility than the corresponding SWCNTs and show periodicity on tube diameters.
Co-reporter:Bing Yin;Guo Wang;Yang Wang
Journal of Molecular Modeling 2010 Volume 16( Issue 3) pp:437-446
Publication Date(Web):2010 March
DOI:10.1007/s00894-009-0560-8
Two groups of isoelectronic molecules with different SiXN (X=C, N, O ) units are analyzed by a combined DFT and NBO study to investigate the electronic basis of Si···N-β-donor bond. The influence of various energy components on the formation of Si···N-β-donor bond is explored. The importance of the electron delocalization from the lone pair of nitrogen atom into the acceptor-orbitals connected with Si atom is elicited by our calculations. The electron delocalization from the lone pair of nitrogen atom into the antibonding orbital of Si-X bond is quite different among the isoelectronic molecules with various types of SiXN units.
Co-reporter:Hongcun Bai, Ruiying Du, Weiye Qiao, Yuanhe Huang
Journal of Molecular Structure: THEOCHEM 2010 Volume 961(1–3) pp:42-47
Publication Date(Web):15 December 2010
DOI:10.1016/j.theochem.2010.08.033
The dumbbell-shaped dimers constructed from C50 cages are investigated using self-consistent field molecular orbital method based on density functional theory. Our study focuses on the structures, stabilities, electronic and vibrational properties of the C50 dumbbell-shaped dimers. It is found that the stability of these C50 dimers is related to bonding positions and linking patterns. For the dimers by [2 + 2] cycloaddition, a simple rule is proposed to predict the stabilities of these additive products of fullerenes according to the environment around the C–C bonds on the addition position. Moreover, higher thermodynamic stability is accompanied with larger HOMO–LUMO gaps for these dimers. The vibrational properties of the C50 dimers are also discussed in this paper.
Co-reporter:Yang Wang, Yuanhe Huang, Baohua Yang, Ruozhuang Liu
Carbon 2008 Volume 46(Issue 2) pp:276-284
Publication Date(Web):February 2008
DOI:10.1016/j.carbon.2007.11.043
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.
Co-reporter:Guo Wang, Yuanhe Huang
Journal of Physics and Chemistry of Solids 2008 Volume 69(Issue 10) pp:2531-2534
Publication Date(Web):October 2008
DOI:10.1016/j.jpcs.2008.05.011
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.
Co-reporter:Yang Wang, Yuanhe Huang, Bing Yin, Baohua Yang and Ruozhuang Liu
The Journal of Physical Chemistry A 2008 Volume 112(Issue 33) pp:7643-7651
Publication Date(Web):July 25, 2008
DOI:10.1021/jp801332b
This work focuses on the computational design and characterization of a novel series of endohedral carborane clusters containing octacoordinate carbon centers. The structural and bonding features and the thermodynamic and kinetic stabilities are discussed extensively based on density functional theory calculations. These nonclassical carboranes are fascinating in structure not only for the octacoordinate carbon center but also for the surrounding carbon and boron ligands with inverted bonding configuration. These endohedral carboranes are higher in energy than the corresponding exohedral isomers due to the high strain in the system. A new stability rule based on the donor−acceptor model is proposed to predict the stability ordering for these carborane isomers. In addition, some of these octacoordinate carboranes might have relatively high kinetic stabilities, which is rather hopeful for the experimental syntheses.
Co-reporter:Guo Wang and Yuanhe Huang
The Journal of Physical Chemistry C 2008 Volume 112(Issue 25) pp:9128-9132
Publication Date(Web):May 30, 2008
DOI:10.1021/jp7108253
A density functional study on transition-metal-coated single-walled carbon nanotubes shows that there are both magnetic and nonmagnetic materials, depending on the nature of the transition metals and their adsorption sites. Adsorption of transition metal atoms to a nanotube is energetically favorable. It is found that some of the magnetic materials exhibit large magnetic moments and high spin polarizations, whereas nonmagnetic materials can display high superconducting transition temperatures.
Co-reporter:Bing Yin;Guo Wang;Niya Sa
Journal of Molecular Modeling 2008 Volume 14( Issue 9) pp:789-795
Publication Date(Web):2008 September
DOI:10.1007/s00894-008-0303-2
Bonding analysis is performed on alternant B16N16 cage based on a combined study of DFT with NBO method. The main feature of such analysis is the separation of bonding structure into two components: σ skeleton and π bond system. Each component is further decomposed into contributions from various NBOs, thus we obtain the details of bonding interactions of every BN unit. Based on these results, relative stability of four covalent dimers of B16N16 is predicted and this prediction is verified by DFT calculations. So the possibility of forecasting properties of oligomers just from analysis on monomer is highlighted in this way.
Co-reporter:Yang Wang Dr. ;Ruozhuang Liu
Chemistry - A European Journal 2006 Volume 12(Issue 13) pp:
Publication Date(Web):21 FEB 2006
DOI:10.1002/chem.200501320
A new series of hydrocarbon cages containing hexa- and octacoordinate carbon centers were designed theoretically by performing DFT calculations at the B3 LYP/6–311+G** level. Among these non-classical structures that were found to still obey the 8e rule, the two tetracations with octacoordinate carbons may be the first examples found in pure hydrocarbons. Structural characteristics, as well as thermodynamic and kinetic stabilities, were also investigated theoretically for these two octacoordinate tetracations. These hydrocarbon compounds containing hypercoordinate carbon centers provide a challenge for synthetic organic chemists.
Co-reporter:Yang Bao-Hua;Wang Yang;Huang Yuan-He
Chinese Journal of Chemistry 2005 Volume 23(Issue 4) pp:
Publication Date(Web):11 MAY 2005
DOI:10.1002/cjoc.200590370
The structures and electronic properties for C36 encapsulated in four single-wall armchair carbon nanotubes (C36@(n,n), n=6-9) were calculated using ab initio self-consistent field crystal orbital method based on density functional theory. The calculations show that the interwall spacing between the carbon nanotube and C36 plays an important role in the stabilities of resultant structures. The optimum interwall spacing is about 0.30 nm and the tubes can be considered as inert containers for the encapsulated C36. The Fermi levels and relative position of energy bands also have something to do with the interwall spacing. The shifts of Fermi level and C36-derived electron states modulate the electron properties of these structures. The extra electrons fill the bands of C36@(8,8) with the optimum interwall spacing almost in a rigid-band manner.
Co-reporter:Yuanhe Huang, Yuanmei Chen, Ruozhuang Liu
Journal of Physics and Chemistry of Solids 2000 Volume 61(Issue 9) pp:1475-1481
Publication Date(Web):September 2000
DOI:10.1016/S0022-3697(00)00006-8
The band structures of several one-dimensional C36 model polymers are calculated using the self-consistent field crystal orbital method. It is found that all the polymers are semiconductors with finite energy gaps. The polymer with D6h symmetry is the most stable one with smallest energy gap among all models studied here. Provided a half-filled band model with doping of electron donor atoms, a roughly semiquantitative estimation gives that the intramolecular electron–phonon coupling cannot lead to a high temperature superconducting phase transition in the polymer with D6h symmetry due to small value of the density of states at Fermi level. A structure with lower symmetry has larger value of the density of states, but too narrow bandwidth may result in strong electron–electron correction suppressing the superconductivity.
Co-reporter:Yuanhe Huang, Jipeng Gao, Ruozhuang Liu
Synthetic Metals 2000 Volume 113(Issue 3) pp:251-255
Publication Date(Web):3 June 2000
DOI:10.1016/S0379-6779(00)00212-5
The structure and electronic properties of nitrogen-containing carbon nanotubes are investigated using self-consistent field crystal orbital method. The models of these tubes are constructed by substitution of some carbon atoms with nitrogen atoms in the armchair carbon nanotube. The calculated band structures show that these nanotubes can be metals or semiconductors depending on the relative position of nitrogen and carbon atoms. The most stable non-metallic tubes are narrow energy gap (EG) semiconductors. Metallic tubes have two overlapped partially filled bands. The influence of Fermi vector positions on metal–insulator phase transition is discussed in the metallic NC tubes.
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