Graphene, its production, properties and applications in electronics etc.
Graphene is the strongest material on Earth. 300 times stronger than steel. Graphene sheet with area of one square meter and a thickness of only one atom, capable of holding an object with a mass of 4 kilograms. Graphene, as the cloth can bend, fold, stretch. Paper towel torn in his hands. With graphene that won’t happen.
Properties and benefits of graphene
The physical properties of graphene
Other forms of carbon: graphene, reinforced – reinforcement graphene, carbyne, diamond, fullerene, carbon nanotube, “Vickery”.
Description of graphene:
Graphene is a two – dimensional allotropic form of carbon in which hexagonal crystal lattice atoms form a layer one atom thick. The atoms of carbon in graphene are interconnected sp2-bonds. Graphene literally is a matter tissue.
Carbon has many allotropes. Some of them, for example, diamond and graphite, have long been known, while others have been discovered relatively recently (10-15 years ago) – fullerenes and carbon nanotubes. It should be noted that known for many decades, graphite is a stack of graphene sheets, i.e., contains multiple graphene planes.
On the basis of the obtained graphene materials: graphene oxide, a hydride of graphene (called graphane) and fluorography (the product of the reaction of graphene with fluorine).
Graphene has unique properties that allows its use in various fields.
Properties and benefits of graphene:
– graphene is the strongest material on Earth. 300 times stronger than steel. Graphene sheet with area of one square meter and a thickness of only one atom, capable of holding an object with a mass of 4 kilograms. Graphene, as the cloth can bend, fold, stretch. Paper towel torn in his hands. With graphene will not happen
– thanks to a two-dimensional structure of graphene, it is a very versatile material that can be used, for example, for weaving strands of rope and other structures. While the thin graphene “rope” in strength will be similar to the thick and heavy steel rope,
in certain circumstances, the graphene activates another ability that allows him to “heal” the “holes” in its crystalline structure in case of damage
– graphene has higher electrical conductivity. Graphene has almost no resistance. From graphene to 70 times the mobility of electrons is higher than that of silicon. The speed of electrons in graphene is 10 000 km/s, although in a conventional conductor, the velocity of the electrons of order 100 m/s.
– has a high capacitance. The specific energy of the graphene is approaching 65 kW*h/kg; This figure is 47 times that are so common nowadays lithium-ion batteries,
– has a high conductivity. It is 10 times teploprovodna copper,
– typical full optical transparency. It absorbs only 2.3% of the light,
– grapheme film passes water molecules and thus delaying everyone else, so you can use it as a filter for water,
the lightest material. 6 times lighter pen
– inertness to the environment,
– soaks up radioactive waste
– due to Brownian motion (thermal fluctuations) of carbon atoms in the graphene sheet the latter is able to “produce” electrical energy,
– is the basis for the Assembly of various independent two-dimensional materials two-dimensional layered heterostructures
– when the flow of salt water on a graphene sheet the latter is able to generate electrical energy by converting the kinetic energy of the flow of salt water into electricity (the so-called electrokinetic effect).
The physical properties of graphene*:
|Name of the parameter:||Value:|
|The bond length C–C, nm||0,142|
|The specific surface area, m2 /g||2630|
|Electron mobility, cm2/(In with)||Of 1.5 × 104|
|The Young’s Modulus, TPA||1|
|Thermal conductivity, W/(m K)||Of 5.1 × 103|
* at room temperature.
The main methods of producing graphene are:
– micromechanical exfoliation of layers of graphite (Novoselov method – method of duct tape). A sample of graphite was placed between the strips of tape and consistently otshelushivaet layers until he was left the last thin layer composed of graphene,
– dispersion of graphite in aqueous media,
– mechanical exfoliation;
– epitaxial growth in vacuum;
– chemical vapor cooling (CVD-process),
– the method of “exudation” of carbon from solutions of the metals or by decomposition of carbides.
Obtaining graphene at home:
It is necessary to take a kitchen blender with a capacity of at least 400 watts. In the bowl of a blender pour 500 ml of water, adding the liquid of any 10-25 milliliters of detergent and 20-50 grams of crushed slate pencil from a pencil. Then the blender needs to work from 10 minutes to an hour until the appearance of a suspension of graphene flakes. The resulting material will possess a high conductivity that will allow it to be used in the electrodes of solar cells. Also produced in a domestic environment, graphene is able to improve the properties of the plastic.
The use of graphene:
– solar energy
– water treatment, water filtration, seawater desalination,
– electronics (LCD monitors, transistors, integrated circuits,etc.)
– in batteries and energy sources. Graphene battery allows the car without recharging to overcome 1000 km, the charging time is not more than 16 seconds
– medicine. Scientists have discovered that graphene flakes of graphene oxide accelerate the reproduction of stem cells and the regeneration of bone cells,
– the creation of super-composites,
– purification of water from radioactive contamination. Graphene oxide rapidly removes radioactive substances from contaminated water. Flakes of graphene oxide bind quickly with natural and artificial radionuclides and condense them and turn them into solids. Themselves the flakes are soluble in liquids and easily produced in industrial scale.