Graphene block chain

1.

The structure of graphene is as follows:

graphene has excellent optical, electrical and mechanical properties, and has important application prospects in materials science, micro nano processing, energy, biomedicine and drug delivery, which is considered as a revolutionary material in the future

Andre Geim and Konstantin Novoselov, physicists from Manchester University, UK, successfully separated graphene from graphite by micromechanical stripping method, so they jointly won the 2010 Nobel prize in physics. The common methods of graphene powder proction are mechanical exfoliation, redox, SiC epitaxial growth, and the film proction method is chemical vapor deposition (CVD)

extended data:

chemical properties:

the chemical properties of graphene are similar to that of graphite. Graphene can adsorb and desorb various atoms and molecules. When these atoms or molecules act as donors or acceptors, the carrier concentration of graphene can be changed, while graphene itself can maintain good conctivity

However, when other substances such as H + and oh - are adsorbed, some derivatives will be proced, which makes the conctivity of graphene worse, but no new compounds are proced. Therefore, we can use graphite to speculate the properties of graphene

for example, the formation of graphene is based on two-dimensional graphene, each carbon atom is added with one more hydrogen atom, so that the SP2 carbon atom in graphene becomes SP3 hybrid. Soluble fragments of graphene can be prepared by chemically modified graphite in the laboratory

2. Graphene is hexagonal, and its π Electrons are conjugated, but not like graphite
it is not only the thinnest known material, but also very firm and hard; As a simple substance, it can transfer electrons faster than any known conctor at room temperature. Graphene has a very special structure on the atomic scale, which can only be described by relativistic quantum physics
the structure of graphene is very stable, so far, researchers have not found the absence of carbon atoms in graphene. The connection between the carbon atoms in graphene is very flexible. When the external mechanical force is applied, the surface of the carbon atoms is bent and deformed, so that the carbon atoms do not have to rearrange to adapt to the external force, and the structure is stable
this stable lattice structure makes carbon atoms have excellent electrical conctivity. When electrons in graphene move in orbit, they will not be scattered e to lattice defects or introction of foreign atoms. Because of the strong interatomic force, at room temperature, even if the surrounding carbon atoms collide, the interference of electrons in graphene is very small.

3. The structure of 1-graphene
graphene is a kind of two-dimensional crystal with single atomic layer formed by carbon atoms connected by SP2 hybrid, and the carbon atoms are regularly arranged in the honeycomb lattice structure unit. Each carbon atom is divided by σ The bond is connected to the other three carbon atoms π The interaction between electrons and other carbon atoms π Large delocalization of electron formation π In this region, electrons can move freely, so graphene has excellent conctivity. At the same time, the close packed honeycomb structure is also the basic unit of other carbon materials. The graphene with single atomic layer can be wrapped to form zero dimensional fullerene, and the graphene with single or multi layers can be curled to form single-walled or multi walled carbon nanotubes

because of the thermodynamic instability of two-dimensional crystal, graphene is not completely flat whether it exists in free state or deposited on the substrate, but there are intrinsic micro scale folds on the surface. The transverse scale of the micro fold is in the range of 8-10nm, and the longitudinal scale is about 0.7-1.0nm. This three-dimensional change can cause the generation of static electricity, so that the graphene monolayer is easy to aggregate. At the same time, the electrical and optical properties of graphene vary with the fold size
in addition to surface wrinkles, graphene is not perfect in practice, but has various kinds of defects, including morphological defects (such as five membered rings, seven membered rings, etc.), voids, edges, cracks, heteroatoms, etc. These defects will affect the intrinsic properties of graphene, such as electrical and mechanical properties. However, some artificial methods, such as high-energy radiation, chemical treatment and so on, can intentionally change the intrinsic properties of graphene, so as to prepare graphene devices with different performance requirements

the properties of 2-graphene
graphene has many excellent physical properties e to its unique monolayer structure. As mentioned earlier, every carbon atom in graphene has an unbound atom π Electrons, which can form perpendicular to the plane π Orbit, π Electrons can travel in this long range π Free movement in the orbit gives graphene excellent electrical conctivity. The results show that the mobility of streamer in graphene can reach 150000 cm2 / (v.s) at room temperature, which is equivalent to 1 / 300 of the speed of light. Under certain conditions, such as the temperature of liquid helium, it can reach 25000 cm2 / (v.s), which is far more than other semiconctor materials. Moreover, the movement of electrons in the lattice is barrier free and will not scatter, which makes it have excellent electron transport properties. At the same time, the unique electronic structure of graphene also makes it show many unique electrical properties, such as room temperature quantum Hall effect
each carbon atom in graphene combines with three adjacent carbon atoms to form a strong bond σ Graphene also shows excellent mechanical properties. According to Columbia University scientists using atomic force microscope to directly test the mechanical properties of single-layer graphene, it is found that the young's molus of graphene is about 1100gpa, and the fracture strength is up to 130gpa, which is 100 times higher than the best steel
graphene is also an excellent thermal conctor. Because of the low carrier density in undoped graphene, the heat transfer of graphene mainly depends on the transfer of phonons, while the heat conction of graphene caused by electron motion is negligible. Its thermal conctivity is as high as 5000W / (m.k), which is superior to that of carbon nanotubes and more than 10 times higher than that of some common metals such as gold, silver and copper

in addition to the excellent conctivity and mechanical properties, graphene also has some other novel properties. Graphene has ferromagnetic properties e to the lone pair electrons at the edge and defects of graphene. The special structure of graphene monolayer makes the theoretical specific surface area of graphene as high as 2630m2 / g. Graphene also has unique optical properties. The transmittance of single-layer graphene in the visible region is more than 97%. These properties make graphene the most potential and imaginative material, which can be widely used in nano devices, sensors, hydrogen storage materials, composite materials, field emission materials and other important fields.

4. Hello, with professional software, 3dsmax can draw some three-dimensional.

5.

graphene is a kind of honeycomb planar film formed by SP2 hybridization of carbon atoms. It is a quasi two-dimensional material with only one atomic layer thickness, so it is also called monatomic layer graphite. Its thickness is about 0.335nm, and there are different unlations according to the different preparation methods. The vertical height is about 1nm, and the horizontal width is about 10nm to 25nm. It is the basic structural unit of all carbon crystals (zero dimensional fullerene, one-dimensional carbon nanotubes, three-dimensional volume oriented graphite) except diamond< br />

6. Graphene graphene was prepared in 2004 by Andre K Geim of the University of Manchester in the UK. Haim and his colleagues came across a new and easy way. They forced the graphite to separate into smaller pieces, separated the thinner graphite flakes from the fragments, then stuck the two sides of the flakes with a special plastic tape, tore the tape, and the flakes split into two. By repeating this process, you get thinner and thinner sheets of graphite, some of which consist of only one layer of carbon atoms - they make graphene
the advent of graphene has caused a worldwide research boom. It is not only the thinnest known material, but also very firm and hard; As a simple substance, it can transfer electrons faster than any known conctor at room temperature. Graphene has a very special structure on the atomic scale, which can only be described by relativistic quantum physics
the structure of graphene is very stable, so far, researchers have not found the absence of carbon atoms in graphene. The connection between the carbon atoms in graphene is very flexible. When the external mechanical force is applied, the surface of the carbon atoms is bent and deformed, so that the carbon atoms do not have to rearrange to adapt to the external force, and the structure is stable
this stable lattice structure makes carbon atoms have excellent electrical conctivity. When electrons in graphene move in orbit, they will not be scattered e to lattice defects or introction of foreign atoms. Because of the strong interatomic force, at room temperature, even if the surrounding carbon atoms collide, the interference of electrons in graphene is very small
the biggest characteristic of graphene is that the velocity of electrons reaches 1 / 300 of the speed of light, which is far faster than that of electrons in general conctors. This makes the electrons in graphene, or more accurately, the "electric charge carrier", very similar to relativistic neutrinos
in order to further explain the special properties of the loaders in graphene, we first make some understanding of relativistic quantum mechanics or quantum electrodynamics
in classical physics, when an electron with lower energy encounters a potential barrier, if the energy is not enough to make it climb to the top of the barrier, it can only stay on this side; In quantum mechanics, electrons are, to some extent, waves that are distributed all over space. When it encounters a barrier, it may penetrate it in some way. This possibility is a number between zero and one; When the electron wave in graphene moves to the front of the barrier at a very fast speed, it needs to be explained by quantum electrodynamics. Quantum electrodynamics makes a more surprising prediction: the electron wave can appear 100% on the other side of the barrier
the following experiments confirm the prediction of Quantum Electrodynamics: first, a voltage (equivalent to a potential barrier) is artificially applied on a piece of graphene crystal, and then the conctivity of graphene is measured. It is generally believed that the resistance will increase with the increase of extra barrier, but this is not the case, because all particles have quantum tunneling effect, and the passing rate is 100%. This also explains the super conctivity of graphene: relativistic loaders can travel through it completely freely
in addition, it is also found that although graphene has only a single atomic thickness, it has considerable opacity: it can absorb about 2.3% of visible light. This is also the embodiment of the relativistic properties of the loaders in graphene. Two Chinese scientists from Columbia University recently discovered that a two-dimensional carbon crystal called graphene in pencil graphite is even harder than diamond, and its strength is 100 times higher than the best steel in the world. The material opens a door to Alibaba for the manufacture of super tough cables for space elevators, making the 23000 mile long space elevator that scientists have long dreamed of possible
Chinese scientists have found the hardest substance
no one would have thought that pencil contains the strongest substance on earth
the French emperor Napoleon once said, "the pen is more powerful than the sword". However, when he said this 200 years ago, he would never have thought that the ordinary pencil used by human beings actually contains the most powerful material on earth! Two Chinese scientists from Columbia University recently found that a two-dimensional carbon crystal called graphene in pencil graphite is harder than diamond and 100 times stronger than the best steel in the world
the discoverers are two Chinese scientists.
the familiar pencil is made of graphite, which is formed by the lamination of numerous "graphene" sheets with only the thickness of carbon atoms. Graphene is a kind of single-layer carbon surface material stripped from graphite material, which is a two-dimensional structure of carbon. Since the discovery of graphene in 2004, the relevant scientific research has never stopped. However, it is only recently that American scientists have confirmed for the first time the long-standing suspicion that graphene is the strongest material known in the world< It is reported that this amazing scientific discovery was made by Li Chenggu and Wei Xiaoding, two Chinese scientists from Columbia University in the United States. One of Li Chenggu's main tools for studying the strength of "graphene" is ordinary transparent tape! "In order to understand the strength of graphene, we must first peel some graphene flakes from the graphite, so we thought of transparent tape," Li explained to reporters The scientists first stuck the tape to a piece of graphite, then tore it off. Then they stuck the tape to a silicon chip with an area of only one square inch, and then tore the tape off the silicon chip. At this time, thousands of small pieces of graphite adhered to the silicon chip
harder than a diamond
there are thousands of holes in a silicon wafer that cannot be seen by the naked eye. Scientists began to take high-tech means to place silicon under an electron microscope for observation. Scientists spent several days, hoping to find a suitable graphene sheet with single atom thickness on the hole of silicon
once scientists found some graphene flakes only one hundredth the width of a human hair, they began to test their strength by puncturing them with metal and diamond probes of atomic size. What shocked scientists is that graphene is stronger than diamond, and its strength is 100 times higher than the best steel in the world
Professor Jeffrey kisa, an American mechanical engineer, explained the strength of graphene in a vivid way: if a sheet of graphene as thin as food preservative film is covered on a cup, and then a pencil is used to pierce it, then an elephant needs to stand on the pencil to pierce the thin sheet of graphene with only the thickness of preservative film
it can be used as a cable for "space elevator"
according to scientists, it is easy to find graphite raw material on the earth, and graphene is the strongest material known to human beings, and it will have many fascinating development prospects. It can not only develop and manufacture ultralight aircraft materials as thin as paper pieces, but also make super tough bullet proof vests, and even open a door for the manufacture of "space elevator" cables. According to US researchers, one of the biggest obstacles to the "space elevator" is how to make a 23000 mile long and strong enough cable from the ground to the space satellite. US scientists have confirmed that graphene, the strongest material on earth, is completely suitable for making space elevator cables
the cost of human entering space through "space elevator" will be much cheaper than that through rocket. NASA has also offered a $4 million reward to encourage scientists to invent tough materials to make space elevator cables< However, according to scientists, although graphite is very common in nature and graphene is the most powerful material known to human beings, it may still take years or even decades for scientists to find a way to transform graphite into a large "thin film" of high-quality graphene, So they can be used to make all kinds of useful materials for human beings
according to scientists, graphene has a series of unique properties in addition to being extremely strong. Graphene is also the most excellent material with electrical conctivity known so far, which makes it also have great application potential in the field of microelectronics. Researchers even see graphene as an alternative to silicon that could be used to make future supercomputers
this kind of material can not only be used to develop ultra light aircraft materials as thin as a piece of paper, but also to make super tough bullet proof vests. It can even make the 23000 mile long space elevator that scientists dream of become a reality.

7. Graphene can be regarded as one of the layers. On this layer, three electrons in the outermost layer of each carbon atom and three surrounding carbon atoms form three σ Bonds, one outermost electron per carbon atom, form large bonds π Conjugate structure.

8. You can see its structure under the microscope. Graphene mainly plays the role of concting electricity; The main problem is to solve its dispersion. Our factory is mainly used to modify graphene in engineering plastics; Heat conction; Enhance the; At present, we use graphene modified engineering plastic particles, used in the proction of procts, the surface conctivity value can be 10 to the third power