As “wonder materials” go, graphene gets all the attention. However, graphyne, an allotrope of graphene, could turn out to be just as useful, if not more so.
Like graphene, a graphyne is a layer of carbon just one atom thick. Unlike graphene, graphyne can take on a range of two-dimensional structures. Graphyne also has both double- and triple-bonded carbon atoms, while graphene has only double bonded atoms. Due to this variety in bond types, there is a huge range of graphyne types, each with double and triple bonds in different configurations.
Electronic qualities
Ever since graphene was first produced in 2004, its distinctive electronic and mechanical qualities have amazed scientists. Experts claim that it might be used in a whole host of device applications, possibly making it the ‘silicon of the 21st century.’
Recent a study indicated that graphyne has strange and possibly useful electronic qualities based in “Dirac cones”, which are structures once thought to be distinctive to graphene. One kind of graphyne with a rectangular lattice is especially interesting due to the effect this geometry has on the Dirac cones - a factor that could prove valuable in establishing new kinds of carbon-based electronic devices. Scientific models have indicated that graphyne's conduction electrons travel very fast, as they do in graphene, but in just one direction. This quality could allow scientists to develop faster transistors and other electronics that handle one-way current.
Research has showed the structural composition of a graphyne has a significant impact on its electrical qualities. In a recent study, researchers looked at three kinds of graphyne: two with hexagonal symmetry and one with rectangular symmetry. Using density-functional theory, the team’s models indicated all three graphynes had Dirac cones, which the researchers said was surprising for the rectangular graphyne it was assumed this kind of structure was only associated with hexagonal symmetry. The study team also found the Dirac cones in the rectangular graphyne were not perfectly conical. This distortion should lead to a conductance that is dependent upon the direction of current flow, a quality not seen in graphene that could be useful in nanoscale electronic devices.
In addition to the structure being a factor in the electronic qualities of graphyne, chemical means can also have an impact on the material's electric qualities, according to computer models. Bonding transition metals onto sheets of graphyne have been revealed to cause substantial modifications in the overall behaviour of the material. When chromium and iron are bonded, graphyne turns into a spin-polarized metal as opposed to a semiconductor. Bonding of other transition metals can trigger either a narrow gap semiconductor or a spin-polarized half semiconductor. These reactions are energetically favourable, which suggests they can be done with an actual sheet of graphyne.
Image credit: Evgeniy Zebolov/Shutterstock
Potential applications
Although the usage of graphyne isn’t common just yet, its qualities are encouraging for quite a number uses, including nanofillers, transistors, sensors and desalinators.
As a nanofiller, Small flakes of graphyne can be distributed in a polymer matrix to boost both rigidity and strength. The edge bonding of the graphyne sheets could expedite the bond of the filler molecules to the matrix, which would raise the efficiency of the filler by blocking separation of the matrix and the graphyne flake.
Studies showing the band gap of graphyne is adjustable via mechanical means suggests it could facilitate the easy manufacturing of transistors with various characteristics that are reliant on band gap. It also enables these qualities to be established much later in the manufacturing method than is achievable with customary semiconductors.
Graphyne is also promising as a desalinator. Its double and triple carbon bonds form holes big enough for water molecules to go through but are not large enough for sodium and chlorine ions. This innate quality of graphyne offers another possibility for the alleviation of fresh water shortages around the world and other related ecological challenges.
Although the usage of graphyne isn’t common just yet, its qualities are encouraging for quite a number uses, including nanofillers, transistors, sensors and desalinators.
As a nanofiller, Small flakes of graphyne can be distributed in a polymer matrix to boost both rigidity and strength. The edge bonding of the graphyne sheets could expedite the bond of the filler molecules to the matrix, which would raise the efficiency of the filler by blocking separation of the matrix and the graphyne flake.
Studies showing the band gap of graphyne is adjustable via mechanical means suggests it could facilitate the easy manufacturing of transistors with various characteristics that are reliant on band gap. It also enables these qualities to be established much later in the manufacturing method than is achievable with customary semiconductors.
Graphyne is also promising as a desalinator. Its double and triple carbon bonds form holes big enough for water molecules to go through but are not large enough for sodium and chlorine ions. This innate quality of graphyne offers another possibility for the alleviation of fresh water shortages around the world and other related ecological challenges.
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