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Graphene (/ ˈ ɡ r æ f iː n /) [1] is a carbon allotrope consisting of a single layer of atoms arranged in a honeycomb planar nanostructure. [2] [3] The name "graphene" is derived from "graphite" and the suffix -ene, indicating the presence of double bonds within the carbon structure.
Graphene is the only form of carbon (or solid material) in which every atom is available for chemical reaction from two sides (due to the 2D structure). Atoms at the edges of a graphene sheet have special chemical reactivity. Graphene has the highest ratio of edge atoms of any allotrope. Defects within a sheet increase its chemical reactivity. [1]
Since carbon nanotubes have a low density for a solid of 1.3 to 1.4 g/cm 3, its specific strength of up to 48,000 kN·m·kg −1 is the best of known materials, compared to high-carbon steel's 154 kN·m·kg −1. Under excessive tensile strain, the tubes will undergo plastic deformation, which means the deformation is permanent. This ...
A news release from the Harvard-Smithsonian Center for Astrophysics described the 2,500-mile (4,000 km)-wide stellar core as a diamond, [49] and it was named as Lucy, after the Beatles' song "Lucy in the Sky With Diamonds"; [50] however, it is more likely an exotic form of carbon. Penta-graphene is a predicted carbon allotrope that utilizes the ...
Single layers of 2D materials can be combined into layered assemblies. For example, bilayer graphene is a material consisting of two layers of graphene. One of the first reports of bilayer graphene was in the seminal 2004 Science paper by Geim and colleagues, in which they described devices "which contained just one, two, or three atomic layers".
A graphene helix, similar to the carbon nanotube, is a structure consisting of a two-dimensional sheet of graphene wrapped into a helix.These graphene sheets can have multiple layers, called multi-walled carbon structures, that add to these helices thus increasing their tensile strength but increasing the difficulty of manufacturing.
Graphene is a semimetal whose conduction and valence bands meet at the Dirac points, which are six locations in momentum space, the vertices of its hexagonal Brillouin zone, divided into two non-equivalent sets of three points. The two sets are labeled K and K′. The sets give graphene a valley degeneracy of gv = 2.
A two-dimensional semiconductor (also known as 2D semiconductor) is a type of natural semiconductor with thicknesses on the atomic scale. Geim and Novoselov et al. initiated the field in 2004 when they reported a new semiconducting material graphene, a flat monolayer of carbon atoms arranged in a 2D honeycomb lattice. [1]