Graphene and its applications EEE2056 Physical Electronics Trimester 2, 2015/2016 Student ID:

What is graphene? In 2004, graphene was isolated from graphite by Sir Andre Geim and Konstantin Novoselov, for which they were awarded the 2010 Nobel Prize in Physics. Graphene is extracted using a method called mechanical exfoliation whereby adhesive tape is placed on graphite to get layers of graphene. The graphene flakes are repeatedly placed on new adhesive tapes to make it thinner and ultimately becomes a single layer of carbon atoms – graphene.

Structure and Properties of Graphene Graphene is an allotrope of carbon. One atom thick which gives graphene its 2D structure, therefore It is extremely thin and lightweight. An excellent conductor. – (Each carbon atom has a delocalized pi bond that permits free-moving electrons which gives rise to its excellent electronic properties.) Extremely strong. –(Has a high tensile strength) Chemically reactive. – (Graphene is the only solid material in which every single atom is available for chemical reaction from two sides due to its 2D structure.) Transparent. – (Transmits about 98% of light.) Self-healing properties. Regular graphene has no band gap, because of this, it acts more like metal. A bandgap can be introduced if an electric displacement field is applied to the bilayer graphene; the material then behaves like a semiconductor.

Applications of Graphene Current products include Samsung’s graphene-coated silicon anode, a more powerful tennis racket claimed by ‘Head’, battery straps by ‘Vorbeck’, graphene- based lightbulbs, and transistors. Graphene is still in its infancy stage. Currently more on improving efficiency of existing materials or substance rather than innovating new products. Has a promising future application: -Rust and weatherproofing – (Combining graphene with paint to form a resistant-coating) -Ultrafiltration – (Graphene Oxide membranes forms a perfect barrier when filtering water. Used to eliminate bacteria and contaminants which can cause waterbourne diseases.) -Graphene Supercapacitors and batteries – (More charging cycles, increased lifespan, can be charged more quickly.)

-Aircrafts and vehicles – (Drastically reduces weight, increased fuel efficiency. The conductive graphene composite coating can measure strain rate interactively.) -Wearable technology – (Has a high tensile strength and is flexible) Drawbacks  The ability to manufacture graphene in large quanties is one of the reasons that slows down the speed of progress of graphene-based devices.  Mechanical exfoliation and chemical vapour deposition(CVD) are not currently cost-effective and are mainly restricted to Research and Development.  Graphene oxide moves easily through bodies of water and could be dangerous. Last year, researchers at Brown University reported that the edges of graphene platelets were capable of cutting and piercing human lung tissue.

Conclusion Graphene is said to be a ‘ wonder material’ due to its almost limitless applicability and feasible properties. Extracted from graphite, it is also abundantly found in nature. Graphene is indeed the next big thing, it is just the matter of time that it will revolutionize the world and enter the next ‘boom’. The structure as well as the unique physical, chemical and electronic properties of graphene were highlighted and discussed. Some of the applications of graphene were listed down and reviewed. Finally, a number of challenges to commercialize graphene were discussed.