Graphene-The magic materials
A material with unusual properties was discovered by scientists in 2004. The hexagonal structure is composed of carbon molecules in a thin atomic layer. Graphene's unique electronic band structure, coupled with relativistic electronics and its rich physical properties, makes it the most ideal electronic two-dimensional system ever discovered.
Graphene has a two-dimensional honeycomb structure and is made up of single layer carbon atoms. It is a basic unit used to construct other dimensional materials. Graphene is a hexagonal honeycomb-shaped crystal made of sp2hybridized atoms. It is only one atom thick. Graphene, although a two dimensional structure, is actually wavy. Each carbon in graphene has a unique bond that connects it to the three surrounding carbons. The electrons can still move freely in graphene, allowing it to conduct electricity. It is possible to consider that the entire graphene sheets forms a large "x" bond.
Preparation and use of the grapheme
Method 1: Tearing tape/slight Friction
The most common preparation method is micromechanical seperation, which involves cutting graphene directly from larger crystalline forms. A typical preparation method involves friction between pyrolytic and a defect or another material. The surface of the bulk graphite forms flocculents crystals that contain graphene in a single layer.
2) Epitaxy Growth on Silicon Carbide Surface
The method involves heating single crystals of silicon carbide to decompose the graphene sheets that are on top. The bulk procedure involves heating the sample by electron bombardment under high pressure after oxygen or hydrogen etching to remove oxides. AES was used to confirm that all oxides on the surface had been removed. The sample was first heated to between 1250-1450 degrees Celsius and then held at this temperature for 20 minutes.
3) Hydrazine reduction method
In a pure solution of hydrazine, a compound consisting of hydrogen and nitrogen atoms, graphene dioxide paper is reduced to monolayers.
4) Sodium ethoxide pyrolysis
First, ethanol must be reduced using nano-metal. After that, the salt produced by ethanol is cracked. Finally, sodium salt can be removed with water. It is possible to obtain graphene. Then, by using mild acoustic and vibration dispersion to prepare graphene in kilogram quantities.
Cutting Carbon Nanotubes
Graphene ribbons can also be made by cutting carbon nanotubes. Cutting multi-walled Carbon Nanotubes in Solution with Potassium Permanganate and Sulfuric Acid is one of the experimental methods. Plasma etching can be used to remove nanotubes that are partially embedded in polymers.
Properties of grapheme
The thinnest known material is also the strongest and most rigid. As a simple compound, it can transfer electrons faster at room temperature than other conductors.
The connection between the carbon atoms is extremely flexible in graphene. When external mechanical force is applied, the surface carbon atoms deform and bend, so the carbon does not have to be rearranged in order to adapt to external forces.
The carbon atoms' excellent conductivity is due to their lattice-like structure. Electrons in graphene that move in orbit do not get scattered by lattice imperfections or foreign atoms. Due to the strong interatomic forces at room temperatures, even when the carbon atoms around graphene collide, there is a very low interference between electrons. This is a great advantage for the use of transparent thin films with conductive properties, which are essential in the field of solar cells and in liquid crystal displays. The graphene material has also shown promising applications in the field of high-sensitivity sensors and energy storage devices.
The most important characteristic of graphene, however, is the fact that electrons in graphene move at 1/300 of the light speed. This is much faster compared to electrons in conductors. It is because of this that the electrons, or better called "loaders", in graphene are similar in nature with relativistic neutrinos. The study also discovered that graphene can absorb about 2,3 times its original thickness, despite only being a single layer.
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