GRAPHENE

You guys might have heard about graphite, the pencil which we uses contains graphite indeed. Graphite is an allotrope of carbon, wait wait, what is an allotrope? The property of an element to exist in two or more different physical forms is termed allotropy. The property difference shown between allotropes are quite amazing. Graphite and diamond are quite famous among the various allotropes, despite both being carbon elements the properties are amazingly different. Diamond being the hardest material known is an insulator whereas graphite is brittle and is a good conductor of electricity and is surprisingly used as a lubricant widely. These distinct behaviour results due to their different crystal structures. In diamond Carbon atoms are arranged in tetrahedral structure, whereas a layered arrangement is present in graphite.

Graphene is something new for us, but not much new to the scientific world. It is an allotrope of Carbon which has a two dimensional hexagonal lattice. Simply it is an one atom layer of graphite. Scientists have discovered graphene years ago, indeed we have come across with graphene in our day to day life. We have unintentionally produced graphite through the use of pencils indeed. Initial observations of graphene goes back to 1960's but unluckily it didn't amazed the scientists at that time. Moreover the method of isolation of graphene was not known at that time. But things changed a lot in 2004 after the isolation process of graphene was discovered by two Russian scientists Andrei Geim and Kostya Novosolev.

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The discovery was really an accidental one, both of them were doing experiments on graphite to investigate on its electrical properties, interestingly they found that they can use sticky tape to peel off thinner layers of graphite, repeated peeling helped them to achieve layers of nearly one atom thick. This invention lead to the discovery of the thinnest material ever known, Graphene and its mind blowing properties amazed the scientific world. Geim and Novosolev were awarded with Nobel Prize for Physics in 2010 for their groundbreaking discovery. A well deserved one indeed.

A playful idea is perfect to start things but then you need a really good scientific intuition that your playful experiment will lead to something, or it will stay as a joke for ever
-Novosolev

What Makes It Special

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Graphene is often referred as the worlds first two dimensional material, the thinnest material ever made with just one atom thickness. Despite of its thickness the properties of Graphene are mind blowing indeed. The most amazing among it is its strength, just one atom thick Graphene material is 200 times stronger than steel, and the sad thing is unluckily diamond lost its first place due to graphenes, but diamonds won't care a lot i suppose because graphenes are their nephews, maybe.

Also it is an excellent conductor of electricity, they indeed have almost zero resistance and is a zero gap semiconductor with electrical conductivity nearly 250 times greater than silicon. Thermal conductivity in graphenes are also high with values nearly 10 times than that of copper. It is almost invisible due to its transparent nature. One of the amazing property of graphenes are when oxidized they forms thin graphene oxides which have high impermiable characteristics. Even the smallest helium molecules doesn't pass through it but interestingly water molecules were able to pass through the membrane. This property can indeed begin a new era in water purification. The reason behind this anomalous behavior is yet to be clearly explained.

FUTURE APPLICATIONS

These amazing properties of graphenes will surely make the production rate exponential and it will replace many of the presently using materials in the near future.

In Electronic Devices

The most promising use of graphenes will be in the electronic industry as a replacement for silicon. The potential is evident from the fact that graphenes coducts electricity faster than any other known materials, its least heat dissipation properties and lesser power consumption. We know that silicon was the wonder material that revolutionized the electronic and IT secors over the last few decades. Likely to that, Graphenes can bring another revolutionary progress in these fields maybe a far bigger one indeed. The transparent nature makes them more effective in usage as onscreen electrodes on monitor screens. The flexible property will be a gamechanger one, we can see flexible mobiles and monitors over the course of one or two years, researches are already being conducted and initial progress is made. The size of almost all electronic devices will further shrink and their effectiveness will make a rapid progress.

In Batteries And Other Storage Devices

Another important application will be in batteries and other energy storage devices. Graphene batteries can last longer, will get charged faster, will be more durable and much lighter. Graphenes have higher energy density and thus can be used to modify the currently using Li- ion and other models and increasing the overall performance of the batteries. Graphenes high surface area to mass ratio and high energy density makes it an ideal supercapacitor. It can be charged and discharged thousands of times with almost no loss in capacitance.
Graphenes can also be used in fuel cells and researches have found that graphene membraned fuel cells increases the efficiency and durability of the system. High thermal conductivity and transparent nature makes it useful in solar cells also. It gives better results than compared to a silicon powered solar cell because of their higher electron emission rate.

As a Remedy For Environmental Challenges

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The unique properties of graphenes including high surface area, higher electrical conductivity and mobility can be a remedy for many present envitmronmental challenges. It can be used as sorbent to reduce environmental decontamination. It is found that they have high sorption tendency towards nuclear and radioactive materials and this property can be used effectively to reduce the rate of radioactive content in our environment. In case of a nuclear calamity Graphene oxide membranes can be a boon to the world. Moreover Graphene oxides are non toxic and biodegradable also.
The magical property of graphenes, that allows penetration of water molecules through their membrane and at the same time is impermiable to even the smallest helium molecules, can be used effectively used in the production of Graphene oxide membranes that might becomes the building block in next generation of water purification and desalination.

Biomedical Applications

Recent researches have revealed that they can be used effectively in many medical uses including drug delivery, biological sensing and imaging, as an antibacterial material for cell culture and in microbiotics. It can be used as a chemical agent to improve the properties in tissue engineering. Graphenes has also been reported as efficient drug delivery agent in cancer therapy.

LIMITATIONS

Graphene, the wonder material will undoubtedly bring upon a revolution along with it, but the problem is, how long will it take? It has been 15 years since it all started. Inspite of its amazing properties we are yet not able to incorporate these industrially. The main reason behind this is that we have not yet discovered a viable method for commercial production. The skotch tape isolation method indeed produces high quality graphenes, but the quantity will be very less and using this method for commercial production of graphenes would make them extremely costly, perhaps the most expensive material ever discovered. Researches are being held and many industrial giants including Samsung and IBM have already invested heavily in it. The profit in the long term is quite promising. A cheap and feasible method that produces high quality graphenes on large scale would be a gamechanger in its development. Many affordable methods available presently compromises on its quality, but the fact is, impure graphenes will loose many of its magical properties and hence it will no longer be a wonder material.

Another limitation would be the absence of band gap which makes it difficult to control the current flow. As a result the flow could not be switched off, making it unsuitable to be used in transistors and other semiconductor devices. Researches are being conducted in finding a suitable dopant that increases the band gap without affecting its conductivity. Until then silicon's will have a safe stand indeed.
It has also been found out that graphene exibits certain toxic nature. In special conditions it is observed to affect the biological functioning of cells disrupting the normal activities. Impure graphenes are found to have this problem. So, only highly pure graphenes could be used in biological and biomedical applications.

CONCLUSION

Graphenes have the potential and ability to replace many present, in use technological developments. But until and unless it's limitations are resolved, it will continue to be a wonder material just in papers.It is quite evident that the situations will change in the near future. The scientific world is keenly waiting for a mere breakthrough that makes its commercialization easier. It has innumerable applications and is vast and ever growing indeed. It has already found its place in the commercial production of tennis racquets and conductive inks, though in small scale. A revolutionary future is very near indeed, let's wait for it.

Have a great day friends. Follow me @sreevin for more interesting posts

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