Angel Bites Piercings

Graphene, new material developed by Andre Geim and Novoselov Konstantin: Nobel Prize in Physics

Graphene

Graphene is a flat sheet structure of an atom thick, composed by atoms of carbon densely packed in a crystal lattice in the form of honeycomb by covalent would be formed from the superposition of the hybrid sp ² bonded carbons.

Sp hybridization 2 is best explained the bond angles, 120 °, the hexagonal structure. As each carbon has four electrons of valence in the hybridized state, three of those electrons will stay in the hybrid sp 2 , forming the skeleton of simple covalent structure and extra electron is accommodated in a p-type atomic orbital perpendicular to the plane of the hybrids. The overlap is side of these orbitals is what would lead to the formation of π-type orbitals. Some of these combinations, among others, would Instead of a giant molecular orbital delocalized among all carbon atoms that form the graphene layer.

The structure of graphite can be considered as a stack of a large number of overlapping graphene sheets. The links between the different layers of graphene stacked is because Van der Waals forces and interactions between the π orbital of carbon atoms.

Graphene is constituted entirely perfect hexagonal cells, the cells are pentagonal and heptagonal defects.

Properties

· High thermal and electrical conductivity (due to its dimensional structure on a honeycomb).

· High elasticity.

· High hardness (almost like the diamond).

· resistance (200 times greater than steel)

· Graphene can react chemically with other substances to form compounds with different properties.

· Supports ionizing radiation .

· is very light, as carbon fiber , but more flexible.

· Minor Joule , unless the lead is heated electrons.

· consumes less power than silicon .

· is almost completely transparent and so thick that neither the helium atom (the atoms are smaller than present) can pass through it.

The discovery of Andre Geim and Novoselov Konstantin

The Nobel Prize in Physics 2010 has been awarded to Andre Geim and Novoselov Konstantin, not for his discovery of graphene, since this was already nearly half a century, but because they discovered how carbon is presented in a way that becomes the material of the future.

Novoselov The finding came about four years ago, when he intuitively with an imaginative approach to isolate graphitic layers of a single atom thick. Graphite, the material from the mines of pencils, is made of layers of carbon atoms arranged like a honeycomb. In this sense, graphene is actually one of these layers that the teacher got Novoselov staining a strip of graphite deposited zeal, painting with a pencil on paper and then using that zeal as a seal on a clean surface.

Kostya Novoselov first manufactured graphene in laboratory in 2004, and July 2008, the scientists had just concluded that it was the toughest material known.

A graphene mesh one atom thick demonstrates its strength to bear the pressure of a diamond stylus.

In March 2007 Professor Andre Geim present a transistor made of graphene. The transistor was more than four times smaller than the smallest made of silicon, as well as more efficient. Was used for making them a sheet of graphene tenth nanometer thick, ie the thickness of a single atom.

Improvements relative to silicon

processors could reach speeds of hundreds of gigahertz (in silicon, the maximum-NonCommercial-is 100 GHz) will take a little more, because graphene is very good driver and passes all the electrons. Silicon, however, is a semiconductor that is, admits that he "tell" when transmitting current and power the millions of transistors that form the processor, and when not.

spoken to "control the conductivity of graphene using two layers of this material, one above another, and in a particular orientation." To fix this problem could also be used graphane, a derivative of graphene: graphane has the same honeycomb structure of graphene, except that it is "sprayed" with hydrogen atoms attached to carbon. The resulting links between the atoms of hydrogen and carbon "bind" the electrons effectively to make such a good driver to graphene. Graphane still retains the thinness, the enormous strength, flexibility and density of its old chemical cousin.

Because graphene is consisting of a single layer thick, the transistors are very sensitive to any molecule that is deposited on its surface. Therefore, it is an ideal material for making chemical and biological sensors.