Application of graphene

At present, the application of graphene is more and more widely used in contemporary society. The application of graphene is worth learning from. Now we have a deep understanding of the application of graphene.

Graphene (Graphene) is a two-dimensional material composed of carbon atoms with sp2 hybridized orbitals, which is a hexagonal flat film with honeycomb lattice. Graphene has long been considered a hypothetical structure, stable in [1] alone, until 2004, the British physicist at the university of Manchester Andre geim and konstantin carbon, successfully in the experiments isolated graphene from graphite, and confirmed it can exist alone, two people also because of "pioneering experiment" in 2 d graphene materials, Shared the 2010 Nobel Prize for physics.

Graphene is currently the thinest and hardest nanomaterial in the world [3]. It is almost completely transparent and absorbs only 2.3% of light. Coefficient of thermal conductivity is as high as 5300 w/m K, higher than that of carbon nanotubes and the diamond, room temperature the more than 15000 cm2 / v. s electron mobility, and higher than carbon nanotubes or silicon crystal *, and the resistance rate is only about 10-6 Ω · cm, lower than that of copper or silver, as the resistivity of the smallest materials [1] in the world. Because of its extremely low resistivity, electrons travel extremely fast and are therefore expected to be used to develop a new generation of electronic components or transistors that are thinner and conduct electricity faster. Because graphene is essentially a transparent, good conductor, it can also be used to make transparent touch screens, light panels and even solar cells.

Another property of graphene is its ability to observe the quantum hall effect at room temperature.

The structure of graphene

Graphene is a two-dimensional (2D) periodic honeycomb lattice structure composed of six-carbon ring, which can be warped into fullerene with zero dimension (0D), rolled into one-dimensional (1D) carbon nanotube (CNT) or stacked into three-dimensional (3D) graphite. Therefore, graphene is the basic unit of graphite materials. The basic structural unit of graphene is the most stable benzene six-element ring in organic materials, which is the most ideal two-dimensional nanomaterial at present. The ideal graphene structure is a planar hexagonal lattice, which can be viewed as a layer of stripped graphite molecules. Each carbon atom is sp2 hybridized and contributes one of the remaining electrons in the p orbital to form a large PI bond. The PI electrons can move freely, giving graphene good electrical conductivity. The two-dimensional graphene structure can be seen as the basic building block for the formation of all sp2 hybrid carbonaceous materials.

Graphene optical properties

According to theoretical derivation, graphene can absorb \ PI \alpha\approx2.3%\,\! The white light; The \ alpha \ \! Is the fine structure constant. A monolayer is not supposed to have this much opacity, and the unique electronic properties of monolayer graphene create this amazing amount of opacity. Because of graphene's unusual low-energy electron structure, electrons and conical bands of holes meet at the Dirac point, resulting in this result. The results were correct, and the opacity of graphene was 2.3\pm0.1%\,\! Is independent of the wavelength of the light wave. However, due to the low accuracy, this method can not be used to determine the fine structure constant measurement standards.

Recently, experiments have demonstrated that at room temperature, the energy gap of graphene can be adjusted from 0eV to 0.25eV (approximately 5 micron wavelength) by applying a voltage to a double-layer graphene field-effect transistor with a double-gate electrode. By applying an external magnetic field, the optical response of the graphene nanoribons can also be adjusted to the terahertz frequency domain [48].

Important properties of graphene

Before graphene was discovered, most, if not all, physicists believed that thermodynamic fluctuations did not allow any two-dimensional crystal to exist at finite temperatures. So its discovery immediately shook condensed matter physics. Although both the theoretical and experimental world believe that a perfect two-dimensional structure cannot be stable at non-absolute zero, monolayer graphene has been prepared experimentally. These may be due to microscopic wrinkles in graphene at the nanoscale.

Graphene also exhibits an anomalous integer quantum hall effect. The hall conductance =2e2/h,6e2/h,10e2/h... Is an odd multiple of the quantum conductance and can be observed at room temperature. This behavior has been interpreted by scientists as "electrons in graphene obey relativistic quantum mechanics and have no static mass". In 2007, three papers claimed that fractional quantum hall effect behavior was observed in p-n or p-n-p junction of graphene. Physical theorists have explained this phenomenon. In 2009, two us teams observed fractional quantum hall effects with a population of 1/3 in graphene. Professor heim has written about the progress and future prospects of graphene research.

To sum up, this paper has explained the application of graphene, and I believe you have more and more in-depth understanding of the application of graphene. I hope this paper can be of great reference value to all readers.

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