Why graphene is important
Graphene is an allotrope (different forms of the element) of carbon. Carbon has the most allotropes as an element, a total of 8! Why is this one so important? Other ones like diamond is expensive and is used in drilling and other equipments but graphene is delicate and strong at the same time giving it edge over its other counterparts. In this blog we will explore its properties and its uses.
Graphene is similar to graphite as both have a hexagonal structure of carbon, however graphene is a single large sheet of carbon with 1 free electron as every carbon is bonded with 3 others. Graphene is extremely strong compared to other metals, this comes as a surprise at it’s just a single sheet of carbon.
“Harder than diamond yet more elastic than rubber; tougher than steel yet lighter than aluminium. Graphene is the strongest known material.”
Graphene is 13 times better than copper at conducting electricity even though graphene has only 1 free electron per atom which is half of that of copper. This serious as copper is the 2nd best feasible conductor. Graphene is a great heat conductor and has large surface area. It has an intrinsic strength of 130 GPa and young modulus of 1.0 TPa. This just goes to show how strong one layer of carbon can be and how useful it is to humanity, especially in future inventions where such materials will be in demand.
Graphite is basically layers of graphene and rolled up they make fullerenes which are another allotrope. However a fullerene cannot conduct as the electrons are trapped and it has a much lower melting point. However it can be used to transport medicines to certain parts of the body. Here are important features of graphene which I describe below.
Scientific reasons for properties of graphene:
The sp2 bonds formed by hybridization of the atoms as each carbon bonds with 3 others covalently. These hybridized bonds are strong due to the 3 α-bonds (forms between covalently bonded atoms) in plane and 2 π-bonds (forms between delocalised electrons of atoms, it is weaker than α-bonds). These extremely strong α bonds result in small bond length which is the secret behind graphene’s outstanding properties. The π bonds are between the delocalized electrons of neighbouring atoms. These π bonds are concerned with free electrons and due to many reasons these bonds help in higher electrical conductivity than expected. The π bonds don’t have a significant effect in bonding of graphene.
Graphite has the same structure but due to its layers of carbon which have weak Van der Waal’s force (it is the weakest intermolecular force that can be taken into account. It is produced by attraction between atoms when certain parts of atoms are attracted to another atom nearby due to uneven distribution of electrons within the atom) between each other results in a soft structure where the layers slide over each other easily. This results in a low sublimation point as the layers break apart easily.
The high electrical conductivity is due to the large surface are of every sheet and the special π bonds. The same reason applies to thermal conductivity like electrical conductivity.
Graphene applications:
Energy
Graphene could help humankind improve methods to produce sustainable energy by using advanced solar cells. Graphene has extraordinary electron carrier ability which allows high conductivity. This property can be exploited in photovoltaic cells where they act as electrodes. They also prevent structures like dendrites from producing which may decrease the efficiency of the cell over time. Graphene has many other uses in energy related resources.
Biotechnology
Graphene is the perfect material to make muscles or transport substances to parts of the body. It is unreactive which other substances cannot achieve. Graphene is impermeable to substances passing through thus substances cannot enter the nanotube (it is a cylinder of graphene) unless its modified. The tubes are really small but tough to carry medicines or to help in inspection of certain organs.
Electronics
These uses include sensors where graphene oxide is ultrasensitive allowing the sensors to be accurate and tremendously fast.
The biggest breakthrough is in the electronics department where silicon is replaced by graphene in transistors, this allows electrons to travel 100x faster in a transistor which allows terahertz computing. Graphene has also showed promise as a flash memory but these graphene need to be modified to fit the requirements of the job.
Another important use is in thermal radiation as power density of electronic increase we need to transport the heat away from the electronic material to prevent overheating. Graphene is an excellent conductor of heat, 2x times better than diamond and almost 1000x times cheaper.
There are many other uses like photodetectors, foldable electronics etc.
We have to remember such discoveries come with responsibility, the uses may not seem significant now, however as more people invest into this new material mankind will benefit. Additionally as more discoveries occur we find more uses. Graphene will play a great role in future electronics and measuring data in unmanned machines. Its extraordinary properties are surprising but there is a lot more scientific detail other than the ones mentioned above. Use this link to learn why graphene has such surprising properties. Until then stay tuned for our next blog on science!
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