Graphene is a special-shaped body (morphology) with a single layer of carbon atoms arranged in a hexagonal lattice. It is the basic structural element of many other alien carbons, such as graphite, charcoal, carbon nanotubes and fullerenes. It can be considered as an uncertain aromatic macromolecule and the ultimate example of polycyclic aromatic hydrocarbons.
Graphene has many unusual properties. It is the strongest material that has been tested, which can effectively conduct heat and electricity, and is almost transparent. Graphene shows great nonlinear diamagnetism, which is larger than graphite and can be suspended by neodymium magnet.
Scientists have studied graphene theoretically for many years. For centuries, through the use of pencils and other similar graphite applications, it has inadvertently produced a small amount of substances. It was first observed under the electron microscope of 1962, but it was studied on the support of metal surface. These materials were later rediscovered, separated and completed by Andre Geim and Konstantin Novoselov of Manchester University in 2004. Through the existing theoretical description of its composition, structure and properties, we can understand its research status. This work led to the Nobel Prize in Physics in 20 10 "Graphene, a groundbreaking experiment of two-dimensional materials".
graphene
"Graphene" is a combination of "graphite" and suffix -ene, named by Hanns-Peter Boehm, and a single-layer carbon foil is described in 1962.
The word "cafeen" first appeared in 1987 to describe that graphite is a component of graphite intercalation compound (GICs). Conceptually, GIC is a crystalline salt of intergranular and graphene. The term was also used in the early description of carbon nanotubes, epitaxial graphene and polycyclic aromatic hydrocarbons (PAHs). Graphene can be regarded as an infinitely alternating polycyclic aromatic hydrocarbon (with only six carbon rings). The International Union of Pure and Applied Chemistry pointed out: "In the past, descriptions such as graphite layer, carbon layer or carbon sheet were all used for the term graphene ..." It is incorrect for the single-layer term, which contains the term graphite, meaning three-dimensional structure. When discussing the reaction, structural relationship or other properties of monolayer, only graphene should be used.
Geim defines "isolated or independent graphene" because "graphene is a single atomic plane of graphite, which is essential-it is completely separated from its environment and is considered independent." This definition is narrower than that of IUPAC, which refers to splitting, transporting and suspending graphene. Other forms, such as graphene grown on various metals, such as suspension or transfer to silicon dioxide (SiO), can become independent.
Graphene theory was first discovered by Wallace in 1947 as the starting point to understand the electronic characteristics of three-dimensional graphite. The massless Dirac equation was first proposed by Semenov, Cenzuo and Mailer. Ruess and Vogt published the earliest TEM images of several layers of graphite in 1948. As early as 1962, when Boehm reported the formation of a single graphene sheet of graphene oxide sheet, the early detailed study of graphite layer began.
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Since 1990, people have been trying to make graphite films by mechanical peeling, but before 2004, there was no film thinner than 50- 100. At first, we tried to use atoms to make graphite films, using a stripping technology similar to wire drawing. A multilayer sample with a thickness of 65438 00 nm was obtained.
One of the first patents on graphene production was submitted in June 2002 and approved in 2006. Two years later, in 2004, Geim and Novoselov extracted crystals [7] with single atom thickness from massive graphite and transferred them to thin silicon dioxide (SiO).
On a silicon wafer, graphene is electrically isolated. This cleavage technique directly leads to the first observation of abnormal quantum Hall effect of graphene, which provides direct evidence for the theoretical prediction of massless Dirac fermion predicted by graphene. This result was reported by Geim's research group Kim and Zhang, whose paper was published in the journal Nature in 2005. Heim and Novoselov won prizes for their pioneering research on graphene, especially the 20 10 Nobel Prize in Physics.
In 20 13, the total budget of large-scale research projects funded by the European Commission was10 billion, involving 150 partner organizations.
Once commercial scale production is proved, the commercialization of graphene will proceed rapidly. By 20 17, and 13 years after the first laboratory graphene electronic device came out, an integrated graphene electronic chip had been commercialized and promoted to pharmaceutical researchers in nano-medical diagnosis in San Diego.
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Graphene is a transparent flexible conductor, which provides a guarantee for various materials/devices applications, including solar cells, light emitting diodes (LEDs), touch panels and smart windows or mobile phones. For example, a graphene touchpad module (2D Carbon Graphene Material Co., Ltd.) produced by a China company has been sold to mobile phone, wearable device and home appliance manufacturers in batches.
Other early commercial uses of graphene include fillers, such as printer powder injected with graphene.
Graphene supercapacitor as an alternative energy source for traditional electrolytic batteries. It has the advantages of fast charging, long service life and environmental protection production. At about 20 15, graphene supercapacitors produced by skeleton technology were commercialized for the first time, which were used in some special applications to replace traditional batteries. By 20 17, commercial graphene supercapacitors can be used in industrial power supply applications, with a maximum output power of 1500 kW. In 20 16, Adgero announced a regenerative braking system (KERS) for large trucks, which adopted a graphene-based supercapacitor. In 20 16, Henrik Fisker announced the development of an electric vehicle, which will use graphene supercapacitors instead of lithium-ion batteries.
Compared with lithium-ion batteries, the problem of low energy density is being solved. The goal of the planned electric car is a minimum of 400 miles (640 kilometers). Later, it was announced that Fisk's electric vehicles would still use lithium-ion batteries, but the research on graphene supercapacitors would continue to be provided by nanotechnology companies.