graphene.pdf

8/9/2019 graphene.pdf

1/11

GRAPHENEA Material that can revolutionize the whole world

GRAPHENE

Saksham Agrawal and Tanishq JasoriaGrapheneThe Ultimate Material


2/11

THE STORY OF GRAPHENEIf you've ever drawn with a pencil, you've probably

made graphene. The world's thinnest material is setto revolutionize almost every part of everyday life.

Fascination with this material stems from its remarkable physicalproperties and the potential applications these properties offer forthe future. Although scientists knew one atom thick, two-dimensional crystal graphene existed, no-one had worked outhow to extract it from graphite. That was until it was isolated in2004 by two Russian-born researchers at The University ofManchester, Andre Geim and Kostya Novoselov.


3/11

THE EARLY YEARSGraphene, millions of ultra-thin layers that stack together to formgraphite commonly found in pencils, was first studied as long agoas 1947.

That electric current would be carried by effectively masslesscharge carriers in graphene was pointed out theoretically in 1984,

and the name 'graphene' was first mentioned in 1987 to describethe graphite layers that had various compounds inserted betweenthem. The term was used extensively in work on carbonnanotubes, which are rolled up graphene sheets. Attempts togrow graphene on other single crystal surfaces have beenongoing since the 1970s, but strong interactions with the surfaceon which it was grown always prevented the true properties ofgraphene being measured experimentally.


4/11

WHAT GRAPHENE CAN DO?Graphene. The world's first 2D material. Since its isolation in2004 it has captured the attention of scientists andresearchers worldwide. It is ultra-light, yet immensely tough. Itis 200 times stronger than steel, but is incredibly flexible. It isfire resistant yet retains heat. It is a superb conductor, but noteven helium can pass through it. All this and more. Muchmore.

When graphene is used alone or combined with other materials or substancesthe possibilities are infinite. It is a young material with the potential to create

incredible future technologies and vastly enhance existing products.

So where will graphene take us? How will it change our world? What benefits willit bring to mankind in the near future and the decades to come?

Graphene could revolutionise medicine. Nanotechnology is set to transformmedical procedures. Drugs could be delivered to specific targeted cells.Graphene could pave the way for a step change in the treatment of cancer andconditions such as Parkinson's.

Graphene has enormous potential when used as a membrane to separate

liquids. It could see huge progress in water purificationand treatment indeveloping countries, and even provide more efficient desalinationplants.

Graphene can make the world a safer place. In aircraft technology and cars.Through clothing for the defenceindustry.

Graphene conducts. It means advanced paintscould both reduce corrosion andincrease energy efficiency.

Graphene detects. It could create sensorsthat can detect even minute traces of

gases or dangerous chemicals, or sustainable food packagingthat can let youknow when food has gone off.

Graphene absorbs light and retains it as energy. Add this to its strength andflexibility and bendable mobile phones and cameraswith enormous battery lifeare ever closer. So are wearable electronics, clothing that communicates.These are future technologies which are becoming realistic in our present.


5/11

Graphene has low weight and high strength. Harnessed with polymers andcomposites it could make numerous forms of transportsafer and more fuelefficient.

This is only the start. These are only the first steps. The potential of graphene is

limited only by our imagination.


6/11

THE QUESTIONS EVERYONE'S

ASKINGWhat is graphene?

Graphene is a single layer of carbon atoms arranged in ahexagonal lattice. Its the world's first two-dimensional material.

Why is graphene invisible?

Graphene is the world's thinnest materialone atom thick. To putthis into context, it is almost one million times thinner than ahuman hair. Therefore, on its own it is not visible to the humaneye. However, single-layer graphene can be seen under themicroscope and millions of layers of graphene can be put togetherto create applications. Graphene samples can also be transferredonto wafers, made from silicon and similar materials, or in solublesolutions so they can be seen clearly by the human eye.

When will we start to see graphene applications?

Graphene was isolated in 2004, so its an extremely new material.We expect to see the first products, likely to be graphene screensfor mobile phones and e-paper devices, on general sale in 2015.This will mean from extraction to application in just over 10 years.This is a remarkably quick turnaround for a new material. Furtherapplications may take several years to develop, for example, bio

and medical applications such as drug delivery would need to besubject to clinical trials, laboratory experiments and furtherresearch.


7/11

How does graphene differ from other carbon-relatedbreakthroughs, such as carbon nanotubes?

Carbon nanotubes are, in effect, simply rolled up tubes ofgraphene. Their potential uses have been widely discussed, butfew, if any, applications have yet been made. It is considered thatmany of the current and potential applications of carbonnanotubes may be taken by graphene as it displays enhancedproperties but with greater ease of production and handling. It isgraphenes combination of superlatives that give it its'wondermaterial' title. Other materials individually have superbqualities, but graphene has several all in one. It is thesecharacteristics that provide expectation that graphene will lead toreal-life applications of the future. In addition, the isolation ofgraphene paved the way for a series of other 2D materials, all ofwhich can be combined with graphene to create novelapplications as yet only a figment of our imagination.

Is graphene dangerous?

There are no proven dangers to consumers. However, if you wereto inhale or ingest a nanomaterial such as graphene it couldpotentially be toxic and so producers engaged in themanufacturing process have to act with caution.


8/11

THEMANUFACTURINGPROCESSTechnically, every time you write with a pencil, graphene is produced. One of the mostbeguiling and fascinating aspects of the isolation of graphene is the remarkablesimplicity of how it was extracted from graphite.

Andre and Kostya used humble Scotch tape to painstakingly peel layers from a stick ofgraphite. And, believe it or not, some of our researchers still use this method to producegraphene, because of the high-quality of the material created.

On an industrial scale, however, production methods have advanced greatly. There area few ways to mass-produce graphene, including Chemical Vapour Deposition, where agas containing carbon (such as Methane) is broken down and reassembled on a hot

metallic surface into a sheet of graphene, and Solution Exfoliation, where graphite isblasted into small fragments of graphene using ultrasonic energy.


9/11

TYPES OF GRAPHENEGraphenea single-atom-thick sheet of hexagonally arranged, bonded carbon atoms,either freely suspended or adhered to a substrate. The dimensions of graphene canvary from several nanometers to the macroscale. Monolayer (single-layer) graphene isthe purest from available and is useful for high-frequency electronics. Bi- and tri-layergraphene, two and three layers respectively, display a range of different qualities as thenumber of layers increase, as well as becoming progressively cheaper as the layersmultiply.

Few-layer graphene (FLG) or multi-layer graphene (MLG)a 2D,sheet-like material,either as a free-standing flake or substrate-bound coating, consisting of a small number(between two and about 10) of well-defined, countable, stacked graphene layers of

extended lateral dimension. Individual flakes should still maintain a high aspect ratio.Few-layer graphene or graphene oxide dispersions can have a defined thicknessdistribution. MLG is useful for composite materials, and as a mechanical reinforcement.

Graphene oxide (GO)chemically modified graphene prepared by oxidation andexfoliation. Graphene oxide is a monolayer material with a high oxygen content. Thinmembranes that allow water to pass through but block off harmful gases are a majoruse for GO.

Reduced graphene oxide (rGO)graphene oxide (as above) that has beenreductively processed by chemical, thermal, microwave, photo-chemical, photo-thermal

or microbial/bacterial methods to reduce its oxygen content. Conductive inks are justone potential use for rGO.

Graphite oxidethis precursor to GO is a bulk solid made by oxidation of graphitethrough processes that functionalize the basal planes and increase the interlayerspacing. Graphite oxide can be exfoliated in solution to form (monolayer) grapheneoxide or partially exfoliated to form few-layer graphene oxide.

Graphite nanoplatelets; graphite nanosheets; graphite nanoflakes;2D graphitematerials with a thickness and/or lateral dimension of less than 100 nanometres. Theuse of nanoscale terminology here can be used to help distinguish these new ultrathin

forms from conventional finely milled graphite powders, whose thickness is typicallymore than 100 nanometres. Excellent for electrically conductive composites


10/11

APPLICATIONS

FUTURE

SCOPEThe progress of a technology from the moment of discovery to transformative product isslow and meandering; the consensus among scientists is that it takes decades, evenwhen things go well. Paul Lauterbur and Peter Mansfield shared a Nobel Prize fordeveloping the MRI, in 1973almost thirty years after scientists first understood thephysical reaction that allowed the machine to work. More than a century passed


11/11

between the moment when the Swedish chemist Jns Jakob Berzelius purified silicon,in 1824, and the birth of the semiconductor industry. So we expect that after 20 or 30years we will flexible devices and batteries and superconductors at room temperature.

graphene.pdf

Documents