Graphyne

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Graphyne
Graphyne v2.svg
Chemical structure of graphyne-1
Identifiers
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Graphyne-n varieties, where n indicates the number of carbon-carbon triple bonds in a link between two adjacent hexagons. Graphyne is graphyne-1; graphdiyne is graphyne-2. Graphynes.png
Graphyne-n varieties, where n indicates the number of carbon–carbon triple bonds in a link between two adjacent hexagons. Graphyne is graphyne-1; graphdiyne is graphyne-2.

Graphyne is an allotrope of carbon. Its structure is one-atom-thick planar sheets of sp and sp2-bonded carbon atoms arranged in crystal lattice. It can be seen as a lattice of benzene rings connected by acetylene bonds. The material is called graphyne-n when benzene rings are connected by n sequential acetylene molecules, and graphdiyne for a particular case of n = 2 (diacetylene links).

Contents

Depending on the content of acetylene groups, graphyne can be considered a mixed hybridization, spk, where k can be 1 or 2, [1] [2] and thus differs from the hybridization of graphene (considered pure sp2) and diamond (pure sp3).

First-principles calculations showed that periodic graphyne structures and their boron nitride analogues are stable. The calculations used phonon dispersion curves and ab-initio finite temperature, quantum mechanical molecular dynamics simulations. [3]

History

Graphyne was first theoretically proposed by Baughman et al. in 1987. [4] In 2010, Li et al. developed the first successful methodology for creating graphdiyne films using the Glaser–Hay cross-coupling reaction with hexaethynylbenzene. [5] The proposed approach makes it possible to synthesize nanometer-scale graphdiyne and graphtetrayne, which lack long-range order. In 2019, Cui and co-workers reported on a mechanochemical technique for obtaining graphyne using benzene and calcium carbide. [6] Although a gram-scale graphyne can be obtained using this approach, graphynes with long-range crystallinity over a large area remain elusive.

Although disputed, researchers used alkyne metathesis, while controlling thermodynamics and kinetics, to synthesize graphyne in 2022. [7] [8] Various analytical methods indicate its excellent chemical and thermal stability. A wide-angle X-ray scattering characterization of the obtained graphyne product suggests a unified crystalline structure. [9]

In 2022, the first scalable synthesis of multi-layered γ‑graphyne was successfully performed through the polymerization of 1,3,5-tribromo-2,4,6-triethynylbenzene under Sonogashira coupling conditions. Near-infrared spectroscopy and cyclic voltammetry of the material determined the bandgap as 0.48 ± 0.05 eV, which agrees with the theoretical prediction for graphyne-based materials. [10] [11]

Structure

Through the use of computer models scientists have predicted several properties of the substance on assumed geometries of the lattice. Its proposed structures are derived from inserting acetylene bonds in place of carbon-carbon single bonds in a graphene lattice. [12] Graphyne is theorized to exist in multiple geometries. This variety is due to the multiple arrangements of sp and sp2 hybridized carbon. The proposed geometries include a hexagonal lattice structure and a rectangular lattice structure. [13] Out of the theorized structures the rectangular lattice of 6,6,12-graphyne may hold the most potential for future applications.

Properties

Models predict that graphyne has the potential for Dirac cones on its double and triple bonded carbon atoms.[ citation needed ] Due to the Dirac cones, the conduction and valence bands meet in a linear fashion at a single point in the Fermi level. The advantage of this scheme is that electrons behave as if they have no mass, resulting in energies that are proportional to the momentum of the electrons. Like in graphene, hexagonal graphyne has electric properties that are direction independent. However, due to the symmetry of the proposed rectangular 6,6,12-graphyne the electric properties would change along different directions in the plane of the material. [13] This unique feature of its symmetry allows graphyne to self-dope meaning that it has two different Dirac cones lying slightly above and below the Fermi level. [13] The self-doping effect of 6,6,12-graphyne can be effectively tuned by applying in-plane external strain. [14] Graphyne samples synthesized to date have shown a melting point of 250-300 °C, low reactivity in decomposition reactions with oxygen, heat and light. [12]

Potential applications

It has been hypothesized that graphyne is preferable to graphene for specific applications owing to its particular energy structure, namely direction-dependent Dirac cones. [15] [16] The directional dependency of 6,6,12-graphyne could allow for electrical grating on the nanoscale. [17] This could lead to the development of faster transistors and nanoscale electronic devices. [13] [18] [19] Recently it was demonstrated that photoinduced electron transfer from electron-donating partners to γ-graphyne is favorable and occurs on nano to sub-picosecond time scale. [20]

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A fullerene is an allotrope of carbon whose molecules consist of carbon atoms connected by single and double bonds so as to form a closed or partially closed mesh, with fused rings of five to seven atoms. The molecules may be hollow spheres, ellipsoids, tubes, or other shapes.

A carbon–carbon bond is a covalent bond between two carbon atoms. The most common form is the single bond: a bond composed of two electrons, one from each of the two atoms. The carbon–carbon single bond is a sigma bond and is formed between one hybridized orbital from each of the carbon atoms. In ethane, the orbitals are sp3-hybridized orbitals, but single bonds formed between carbon atoms with other hybridizations do occur. In fact, the carbon atoms in the single bond need not be of the same hybridization. Carbon atoms can also form double bonds in compounds called alkenes or triple bonds in compounds called alkynes. A double bond is formed with an sp2-hybridized orbital and a p-orbital that is not involved in the hybridization. A triple bond is formed with an sp-hybridized orbital and two p-orbitals from each atom. The use of the p-orbitals forms a pi bond.

<span class="mw-page-title-main">Allotropes of carbon</span> Materials made only out of carbon

Carbon is capable of forming many allotropes due to its valency. Well-known forms of carbon include diamond and graphite. In recent decades, many more allotropes have been discovered and researched, including ball shapes such as buckminsterfullerene and sheets such as graphene. Larger-scale structures of carbon include nanotubes, nanobuds and nanoribbons. Other unusual forms of carbon exist at very high temperatures or extreme pressures. Around 500 hypothetical 3‑periodic allotropes of carbon are known at the present time, according to the Samara Carbon Allotrope Database (SACADA).

<span class="mw-page-title-main">Coronene</span> Chemical compound

Coronene is a polycyclic aromatic hydrocarbon (PAH) comprising seven peri-fused benzene rings. Its chemical formula is C
24H
12. It is a yellow material that dissolves in common solvents including benzene, toluene, and dichloromethane. Its solutions emit blue light fluorescence under UV light. It has been used as a solvent probe, similar to pyrene.

<span class="mw-page-title-main">Graphene</span> Hexagonal lattice made of carbon atoms

Graphene is an allotrope of carbon consisting of a single layer of atoms arranged in a hexagonal lattice nanostructure. The name is derived from "graphite" and the suffix -ene, reflecting the fact that the graphite allotrope of carbon contains numerous double bonds.

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<span class="mw-page-title-main">Linear acetylenic carbon</span> Polymer made of repeating −C≡C− units

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<span class="mw-page-title-main">Graphane</span> Chemical compound

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<span class="mw-page-title-main">Rodney S. Ruoff</span> American chemist

Rodney S. "Rod" Ruoff is an American physical chemist and nanoscience researcher. He is one of the world experts on carbon materials including carbon nanostructures such as fullerenes, nanotubes, graphene, diamond, and has had pioneering discoveries on such materials and others. Ruoff received his B.S. in chemistry from the University of Texas at Austin (1981) and his Ph.D. in chemical physics at the University of Illinois-Urbana (1988). After a Fulbright Fellowship at the MPI fuer Stroemungsforschung in Goettingen, Germany (1989) and postdoctoral work at the IBM T. J. Watson Research Center (1990–91), Ruoff became a staff scientist in the Molecular Physics Laboratory at SRI International (1991–1996). He is currently UNIST Distinguished Professor at the Ulsan National Institute of Science and Technology (UNIST), and the director of the Center for Multidimensional Carbon Materials, an Institute for Basic Science Center located at UNIST.

<span class="mw-page-title-main">Silicene</span> Two-dimensional allotrope of silicon

Silicene is a two-dimensional allotrope of silicon, with a hexagonal honeycomb structure similar to that of graphene. Contrary to graphene, silicene is not flat, but has a periodically buckled topology; the coupling between layers in silicene is much stronger than in multilayered graphene; and the oxidized form of silicene, 2D silica, has a very different chemical structure from graphene oxide.

Silicynes are allotropes of silicon.

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<span class="mw-page-title-main">Carbon nanothread</span>

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<span class="mw-page-title-main">Penta-graphene</span> Chemical compound

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References

  1. ↑ Heimann, R.B.; Evsvukov, S.E.; Koga, Y. (1997). "Carbon allotropes: a suggested classification scheme based on valence orbital hybridization". Carbon . 35 (10–11): 1654–1658. doi:10.1016/S0008-6223(97)82794-7.
  2. ↑ Enyashin, Andrey N.; Ivanovskii, Alexander L. (2011). "Graphene Allotropes". Physica Status Solidi B . 248 (8): 1879–1883. Bibcode:2011PSSBR.248.1879E. doi: 10.1002/pssb.201046583 . S2CID   125591804.
  3. ↑ Özçelik, V. Ongun; Ciraci, S. (January 10, 2013). "Size Dependence in the Stabilities and Electronic Properties of α-Graphyne and Its Boron Nitride Analogue". The Journal of Physical Chemistry C. 117 (5): 2175–2182. arXiv: 1301.2593 . doi:10.1021/jp3111869. S2CID   44136901.
  4. ↑ Baughman, R. H.; Eckhardt, H.; Kertesz, M. (1987). "Structure‐property predictions for new planar forms of carbon: Layered phases containing sp2 and sp atoms". The Journal of Chemical Physics. 87 (11): 6687–6699. Bibcode:1987JChPh..87.6687B. doi:10.1063/1.453405.
  5. ↑ Li, G.; Li, Y.; Lui, H.; Guo, Y.; Li, Y.; Zhu, D. (2010). "Architecture of graphdiyne nanoscale films". Chemical Communications. 46 (19): 3256–3258. doi:10.1039/B922733D. PMID   20442882.
  6. ↑ Li, Q.; Yang, C.; Wu, L.; Wang, H.; Cui, X. (2019). "Converting benzene into γ-graphyne and its enhanced electrochemical oxygen evolution performance". Journal of Materials Chemistry A. 7 (11): 5981–5990. doi:10.1039/C8TA10317H. S2CID   104431102.
  7. ↑ Hu, Yiming; Wu, Chenyu; Pan, Qingyan; Jin, Yinghua; Lyu, Rui; Martinez, Vikina; Huang, Shaofeng; Wu, Jingyi; Wayment, Lacey J.; Clark, Noel A.; Raschke, Markus B.; Zhao, Yingjie; Zhang, Wei (9 May 2022). "Synthesis of γ-graphyne using dynamic covalent chemistry".
  8. ↑ Hu, Y.; Wu, C.; Pan, Q.; Jin, Y.; Lyu, R.; Martinez, V.; Huang, S.; Wu, J.; Wayment, L.J.; Clark, N.A.; Raschke, M.B.; Zhao, Y.; Zhang, W. (2022). "Synthesis of γ-graphyne using dynamic covalent chemistry". Nature Synthesis. 1 (6): 449–454. Bibcode:2022NatSy...1..449H. doi:10.1038/s44160-022-00068-7. S2CID   248686420.
  9. ↑ Leytham-Powell, Cay; Boulder, University of Colorado at. "Long-hypothesized 'next generation wonder material' created for first time". phys.org. Retrieved 2022-05-23.
  10. ↑ Desyatkin, V. G.; Martin, W. B.; Aliev, A. E.; Chapman, N. E.; Fonseca, A. F.; Galvão, D. S.; Miller, E. R.; Stone, K. H.; Wang, Z.; Zakhidov, D.; Limpoco, F. T.; Almahdali, S. R.; Parker, S. M.; Baughman, R. H.; Rodionov, V. O. (2022). "Scalable Synthesis and Characterization of Multilayer γ‑Graphyne, New Carbon Crystals with a Small Direct Band Gap". Journal of the American Chemical Society. 144 (39): 17999–18008. arXiv: 2301.05291 . doi:10.1021/jacs.2c06583. PMID   36130080. S2CID   252438218.
  11. ↑ Kang, Jun; Wei, Zhongming; Li, Jingbo (2019). "Graphyne and Its Family: Recent Theoretical Advances". ACS Applied Materials & Interfaces. 11 (3): 2692–2706. doi:10.1021/acsami.8b03338. PMID   29663794.
  12. 1 2 Kim, Bog G.; Choi, Hyoung Joon (2012). "Graphyne: Hexagonal network of carbon with versatile Dirac cones". Physical Review B . 86 (11): 115435. arXiv: 1112.2932 . Bibcode:2012PhRvB..86k5435K. doi:10.1103/PhysRevB.86.115435. S2CID   119288235.
  13. 1 2 3 4 Dumé, Belle (1 March 2012). "Could graphynes be better than graphene?". Physics World . Institute of Physics.
  14. ↑ Wang, Gaoxue; Si, Mingsu; Kumar, Ashok; Pandey, Ravindra (May 26, 2014). "Strain engineering of Dirac cones in graphyne". Applied Physics Letters. 104 (21): 213107. Bibcode:2014ApPhL.104u3107W. doi:10.1063/1.4880635.
  15. ↑ Malko, Daniel; Neiss, Christian; Viñes, Francesc; Görling, Andreas (24 February 2012). "Competition for Graphene: Graphynes with Direction-Dependent Dirac Cones" (PDF). Phys. Rev. Lett. 108 (8): 086804. Bibcode:2012PhRvL.108h6804M. doi:10.1103/PhysRevLett.108.086804. hdl: 2445/65316 . PMID   22463556.
  16. ↑ Schirber, Michael (24 February 2012). "Focus: Graphyne May Be Better than Graphene". Physics . 5 (24): 24. Bibcode:2012PhyOJ...5...24S. doi:10.1103/Physics.5.24.
  17. ↑ Bardhan, Debjyoti (2 March 2012). "Novel new material graphyne can be a serious competitor to graphene". techie-buzz.com.
  18. ↑ Cartwright, J. (1 March 2012). "Graphyne could be better than graphene". news.sciencemag.org. Archived from the original on 2 October 2012.
  19. ↑ "Graphyne Better Than Graphene?". Materials Today. 5 March 2012.
  20. ↑ Stasyuk, O.A.; Stasyuk, A.J.; Solà, M.; Voityuk, A.A. (2022). "γ-graphyne: a promising electron acceptor for organic photovoltaics". Materials & Design. 225: 111526. doi:10.1016/j.matdes.2022.111526. hdl: 10256/22532 . S2CID   254961210.
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