Understanding the properties and dimensions of graphene is important for understanding novel ways in which the extremely thin, potentially world-changing material can be used.
A 'wonder material'
Graphene has the highest known thermal and electrical conductivity of any material and is tougher than steel while still being light, flexible, and transparent. No wonder it is often called a 'wonder material.'
The material has a wide range of potentially world-changing uses. These include being used as a filter for seawater, a barrier against mosquito nets, and a comfortable solution to electrodes in prosthetic devices.
Comparing graphene and graphite
In a new study, published in the journal Physical Review Letters, researchers asked two key questions: what is the true thickness of graphene, and to what extent is the material graphite?
To the surprise of the scientists, they found that 2D graphene, which is a flat single layer of carbon atoms arranged in a honeycomb structure, has several similarities to the 3D graphite.
Graphene and graphite share a similar resistance to compression. The thickness of graphene, meanwhile, was extrapolated by comparing it to graphite.
If the thickness of a block of graphite 100 layers thick is measured, that means that the thickness of a single graphene layer is equivalent to the thickness of the graphene block divided by 100.
So, based on their calculations, the thickness of graphene is 0.34 nm, the researchers say.
2D or not 2D, that is the question
Dr. Yiwei Sun, the lead author of the study from Queen Mary University of London, said: "Graphene owes its thickness to an array of chemical bonds sticking out above and below the 2D plane of carbon atoms. Hence graphene is really a 3D material, albeit with a very small thickness.
"By applying conventional 3D theory, which has been used for around 400 years, to 2D materials such as graphene, which have been known for 15 years, we show that similar arguments apply to other so-called 2D materials, such as boron nitride and molybdenum disulphide. In that sense, 2D materials are actually all 3D."
Graphene was discovered in 2004 by peeling off graphene flakes from graphite using sticky tape. It is known by many as 'the world's first two-dimensional material', due to the fact that it is extremely thin and is made of a sheet of atoms.