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Graphene is a material that has several properties capable of revolutionizing technology

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Graphene is a material composed of a two-dimensional layer of carbon atoms arranged in hexagonal structures, whose height is equivalent to that of an atom. This material can be produced by extracting surface layers of graphite, an abundant mineral on Earth and one of the most common allotropes of carbon.

The chemical bonds and thickness of graphene are responsible for several important properties of this element, such as mechanical resistance and thermal and electrical conductivities. These features have attracted scientists and the technology industry due to their infinite possibilities of use.

The discovery of graphene

Stable, two-dimensional graphene was accidentally discovered in 2004 by Russian physicists Andre Geim and Konstantin Novoselov. This discovery earned researchers the Nobel Prize in Physics in 2010. However, the existence of this allotrope of carbon has been known since 1930.

Graphene Properties

Graphene has numerous properties that make it a material with several technological applications. Know the main properties of this allotrope.

Mechanical properties

Graphene is the strongest material ever known. This resistance stems from the strong bonds formed between its carbon atoms. Materials widely used in civil construction, such as steel, withstand only a third of this pressure.

Another interesting property of graphene is its high Young's modulus, indicating that, in addition to being resistant, this material is very elastic. Therefore, it is able to return to its original size relatively easily.

The small areas of each carbon hexagon are responsible for the high impermeability of graphene, which can be used as a small net capable of holding gases that easily leak from their containers, such as hydrogen gas. In addition to being extremely resistant, graphene is very light: its density is 0.77 g/m², in other words, about a thousand times lighter than a sheet of paper.

electrical properties

Electrons are able to propagate through graphene almost freely without suffering deflection or collisions. Due to the hexagonal structure of carbon bonds, electrons move inside these thin layers at relativistic speeds, that is, close to the speed of light.

At room temperature, graphene's electrical resistivity is the lowest there is. Thus, this element can be considered the best metallic conductor.

optical properties

By allowing 97.5% of incident light to pass through, graphene is invisible to the naked eye. This optical behavior arises from the relativistic properties of electrons in graphene. This implies that, by stacking several sheets of graphene, it is possible to produce a perfectly black body, capable of absorbing almost all the radiation incident on it.

thermal properties

Due to its electrical properties, graphene is an excellent thermal conductor. This material is capable of dissipating heat faster than any known material. Furthermore, some studies suggest that its melting temperature is 3851 °C.

Therefore, the main properties and characteristics of graphene are:

• It is extremely thin: it is the thickness of an atom;
• It is highly resistant: about 200 times stronger than steel;
• It's flexible;
• It's waterproof;
• It is transparent: transmits about 97.5% of light rays;
• It has high thermal and electrical conductivity: it conducts electrical energy 100 times faster than copper. Studies have also shown that the speed at which electrons travel through graphene is 1000 km/s (60 times faster than silicon);
• It has high hardness
• It has less Joule effect: it loses less energy in the form of heat when conducting electrons.

Graphene Applications

Due to its properties and characteristics, graphene is one of the most promising materials known. Its technological applications are vast, but limited by the capacity to produce this material on a large scale. Devices such as folding LED screens, photovoltaic cells, more efficient transistors, supercapacitors, heat sinks and super cell phone batteries are some examples of technologies developed using graphene.

In addition, graphene can be applied in other areas of study, such as:

Potable water

Graphene-formed membranes are able to desalinate and purify sea water

CO2 emissions

Graphene filters are able to reduce CO2 emissions by separating gases generated by industries and businesses

disease detection

Much faster biomedical sensors are based on graphene and can detect diseases, viruses and other toxins.

Construction

Building materials such as concrete and aluminum become lighter and stronger with the addition of graphene

Aesthetics

Hair coloring by spraying graphene lasts up to 30 washes

Microdevices

Smaller and stronger chips due to the replacement of silicon by graphene

Energy

Solar cells have better flexibility, more transparency and lower production costs with the use of graphene

Electronics

Batteries with better and faster energy storage

Mobility

Bikes can have firmer tires and frames weighing 350 grams using graphene

Among the studies related to graphene, those involving the development of new data transmission cables for the internet stand out. According to a survey published by the magazine Nature Communication, the idea is to take advantage of all the speed reached by the electrons in graphene – the cells move in it hundreds of times faster than in the cables currently used.

Importance of graphene for Brazil

Brazil is part of the technological race in search of cheaper and more efficient methods for the production of graphene. According to the report produced by the National Department of Mineral Production (DNPM), the graphene market should be one of the most profitable in the world, with the potential to reach up to 1 trillion dollars in 10 years. In addition, Brazil has the largest reserves of graphene in the world.

Graphene price

Due to its complex means of obtaining it, the price of graphene is still high. The most current techniques that allow the production of pure and thin layers of this material work with vapor deposition on metallic substrates, such as copper sheets.

Today, a 2.08 cm by 1.54 cm sheet of graphene can cost up to $275: an average of $21 per square inch. However, factors such as impurities and asymmetries can drastically reduce this price. Graphene can also be obtained from graphite: with 1 kg of graphite, which costs approximately 1 dollar, it is possible to produce 150 g of graphene, whose value exceeds 15 thousand dollars.

Curiosities about graphene

• The Graphene Flagship project, from the European Union, earmarked around 1.3 billion euros for research related to graphene, applications and development of production on an industrial scale. In all, 150 institutions from 23 countries participate in this project.
• The first suitcase developed for space travel has graphene in its composition. Its launch is scheduled for 2033, when NASA plans to carry out expeditions to Mars.
• Borophene is graphene's new competitor. This material, discovered in 2015, is seen as an improved version of graphene, being even more flexible, resistant and conductive.