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Graphene-The magic materials in the world.

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Update time : 2019-08-08 15:56:13
A new material with singular properties was discovered in 2004. It is a two-dimensional hexagonal lattice structure consisting of carbon atoms with a single atomic layer or atomic layer thickness. Graphene, with its unique electronic band structure and relativistic electronics, is the most ideal two-dimensional electronic  system discovered so far, and has rich and novel physical properties.

Graphene is a new carbon material with two-dimensional honeycomb lattice structure, which is closely packed by single layer carbon atoms. It is the basic unit for constructing other dimensional carbon materials. Graphene is a kind of hexagonal honeycomb crystal formed by sp²hybridized carbon atoms whose thickness is only a single layer of atoms. Graphene is a two-dimensional structure, but in fact it is not flat, but wavy. Each carbon atom in graphene is connected with three surrounding carbon atoms by a special single bond. The remaining electron can move freely, so graphene can conduct electricity. To some extent, it can be considered that the whole graphene sheet forms a large x bond.
 
Preparation of grapheme
 
1) tearing tape method/slight friction method
The most common method is micromechanical separation, which cuts graphene sheets directly from larger crystals. Typical preparation methods are friction with pyrolytic graphite which is expanded by another material or introduced defect. The surface of bulk graphite produces flocculent crystals, which contain single layer graphene.

2) Epitaxy Growth of Silicon Carbide Surface
The method is to remove silicon by heating single crystal silicon carbide and decompose graphene sheets on the surface of single crystal. The bulk process is to heat the sample after oxygen or hydrogen etching under high vacuum by electron bombardment to remove oxides. Auger electron spectroscopy (AES) was used to determine that the oxide on the surface was completely removed. The sample was heated up to 1250-1450℃and then kept at constant temperature for 1 minute and 20 minutes, thus forming a very thin graphite layer.

3) Hydrazine reduction method
Graphene oxide paper is placed in a pure hydrazine solution (a compound of hydrogen and nitrogen atoms), which reduces graphene oxide paper to monolayer graphene.

4) Sodium ethoxide pyrolysis
Firstly, ethanol is reduced with nano-metal, then the ethanol salt product is cracked, and sodium salt is removed by washing with water. Graphene sticking up is obtained. Then, pure graphene in kilogram quantity can be prepared by vibration dispersion with mild acoustic wave.

5) Cutting Carbon Nanotubes
Cutting carbon nanotubes is also an experimental method for making graphene ribbons. One of the methods is to cut multi-walled carbon nanotubes in solution with potassium permanganate and sulfuric acid. Another method uses plasma etching to etch nanotubes partially embedded in polymers.
 
Properties of grapheme
 
Not only is it the thinnest material known, it is also very strong and rigid; As a simple substance, it transfers electrons at room temperature faster than known conductors.

The connection between carbon atoms in graphene is very flexible. When external mechanical forces are applied, the surface of carbon atoms bends and deforms, so that the carbon atoms do not need to be rearranged to adapt to external forces, thus maintaining structural stability.

This stable lattice structure makes carbon atoms have excellent conductivity. When electrons in graphene move in orbit, they do not scatter due to lattice defects or the introduction of foreign atoms. Because the interatomic force is very strong at room temperature, even if the surrounding carbon atoms collide, the interference of electrons in graphene is very small. This gives it a unique advantage in the application of transparent conductive thin films, which are very important in the fields of liquid crystal display and solar cells. In addition, graphene has shown attractive application prospects in high sensitivity sensors and high performance energy storage devices.

The greatest characteristic of graphene is that the speed of electrons in graphene reaches 1/300 of the speed of light, which is much faster than that of electrons in general conductors. This makes the electrons in graphene, or more accurately, called "loaders", very similar in nature to relativistic neutrinos. In addition, the study also found that graphene has a considerable opacity, although only the original thickness of the single layer: it can absorb about 2.3 times.

TRUNNANO (Luoyang Trunnano Tech Co., Ltd ) is a professional graphene manufacturer with over 12 years experience in chemical products research and development. If you are looking for high quality graphene, please feel free to contact us and send an inquiry.
 
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