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raphene is a single layer of carbon atoms derivedfrom graphite. But that humble description belieshow truly incredible this substance is.

Graphene is the world’s strongest material; it is 200times stronger than steel. It is also the world’sthinnest substance, at one-millionth the width of asheet of paper.

Combining these two properties means that, as onenewspaper explained, a square meter of graphenecould be made into a hammock that would be strongenough to hold a nine-pound cat, while weighing nomore than one of its whiskers.

Graphene is also extremely flexible and stretchable.It conducts both heat and electricity better than anyknown material. It is nearly transparent. It filters

G

Graphene Begins to Unleash the Real Promise

of Nanomaterials

out every type of gas, while allowing water to flowthrough it.

For all these reasons, graphene promises to be agame-changer in many industries. While most peopleare still unaware of what it can do, scientists havebeen making slow but steady progress toward thecommercial development of this “wonder material”

for nearly a century.

In 1916, the structure of graphite was identified,and 31 years later a researcher named P.R. Waltertheorized about the existence of graphene.1

Not long after that, researchers were able to see sin-gle layers of graphene under an electron microscope.

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Today, a wide range of graphene manufacturing technologies have emerged to address specific applications.Over the coming decade, we expect two or three processes to develop clear cost and quality advantages that willenable them to dominate the industry.

GrapheneSynthesisMethods

But there remained no practical way to isolategraphene and use it commercially.

Then, in 2004, at the University of Manchester, sci-entists Andre Geim and Kostya Novoselov made amajor breakthrough: Working with flakes of bulkgraphite, they used pieces of sticky Scotch tape topeel off layers at a time, then kept repeating theprocess until they were left with a single layer, witha thickness of just one atom, which they then trans-ferred to a silicon wafer. For this work, Geim andNovoselov were awarded the 2010 Nobel Prize inPhysics.

Now that graphene can be isolated, the only hurdlethat remains to exploiting its infinite potential incountless applications is that the process to createjust a small amount of graphene is still prohibi-tively expensive. So today the race is on to findways to manufacture graphene cheaply and in largequantities.

One method that is being explored involves elec-trolysis. This approach involves pumping lithiumions between layers of graphite in order to make iteasier to separate each layer of graphene from theothers.2

Another experimental method involves writinggraphene circuitry with ion pens. Scientists fromthe University of Florida have developed a new tech-nique for creating graphene patterns on top of sili-con carbide. Silicon carbide comprises both siliconand carbon, but at high temperatures, silicon atomswill vaporize off the surface, leaving the carbonatoms to grow into sheets of pure graphene.

The team found that implanting silicon or gold ionsin silicon carbide lowered the temperature atwhich graphene formed by approximately 100 de-grees Celsius. The team implanted ions only wheregraphene layers were desired, and then heated the

silicon carbide to 1,200 degrees Celsius.

Using this technique, the team successfully createdgraphene nanoribbons, thin lines of graphene withnanoscale dimensions.

With further refining, the process, described in thejournal Applied Physics Letters, may be able to en-courage selective graphene growth at even lowertemperatures.3

Meanwhile, researchers from the Graphene Re-search Group at Toyohashi University of Technologyreported in the Journal of Physics: Conference Se-

ries that they produced graphene by extracting read-ily available microorganisms from a riverbank nearthe campus.4

One of the reasons why production of graphene is soexpensive and time-consuming is that hydrazine isused in the critical process for achieving chemical re-duction of graphene oxide flakes, and hydrazinevapor is highly toxic.

The team built on research showing that grapheneoxide behaves as a terminal electron acceptor for bac-teria, and is reduced by microbial action in the processof breathing or electron transport. Tests showed thatusing microorganisms from the riverbank reduced thegraphene oxide flakes.

The approach offers a low-cost, highly efficient,and environmentally friendly method for the massproduction of high-quality graphene.

At the same time that these and other approachesare leading toward the commercialization of con-ventional graphene, a parallel pursuit is bringing theconcept of artificial graphene closer to reality.

Unlike conventional graphene, which is made up ofcarbon atoms, artificial graphene is composed of

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Welcome to the Graphene Age

ACloser

Look at

Graphene

silicon. Recently, a team of researchers pub-lished findings in the journal Physical Review X

that indicate artificial graphene can be createdfrom traditional semiconductor materials.5

By working with nanometer-thick semiconductorcrystals, the researchers were able to achieve manyof the same properties as conventional graphene.

As experiments like these bring us closer to the wide-spread production of graphene, what applicationscan we look forward to in the coming years?

Please consider the following forecasts:

First, graphene will enable the commercializa-tion of flexible electronics. Because grapheneretains its strength even when it is stretched, thesenew devices will allow for the production of elec-tronic devices that can be folded like paper to fit intoa purse or pocket.

Second, graphene will revolutionize smart-phones. Because graphene is both transparent andthe world’s best conductor, it will make possibleamazing advances in touchscreen displays. Notonly will they look better, but unlike glass, they willbe as unbreakable as steel. In addition, graphenewill enable smartphone batteries to recharge inmere minutes.

Third, graphene will provide a powerful way toextend Moore’s Law. By replacing silicon chipswith graphene, engineers will be able to design com-puters of all sizes that will pack enormous powerinto a small space. Because graphene dissipatesheat so efficiently, a composite made of grapheneand copper has been found to cool devices fasterthan copper alone. As a result, computers will useless energy.

Fourth, graphene will extend the life of cars

and other products made from steel and othermetals. Tests published in ACS Nano show thatgraphene is highly effective in protecting againstcorrosion.6 In fact, copper coated with graphenecorroded seven times slower than bare copper, andnickel coated with graphene corroded 20 timesslower than bare nickel. A single layer of grapheneprotects as well as conventional organic coatingsthat are more than five times thicker.

Fifth, graphene will provide a highly effectivefilter for purifying wastewater and desalinat-ing seawater. Among graphene’s many uniqueproperties is the fact that it is hydrophobic, mean-ing that it repels water, and yet narrow capillariesmade from graphene attract water. This unusualproperty has attracted intense academic and in-dustrial interest with the intent to develop newwater filtration and desalination technologies.One-atom-wide graphene capillaries can now bemade easily and cheaply by piling layers ofgraphene oxide on top of each other. Two yearsago, University of Manchester researchers discov-ered that thin membranes made from such multi-layer stacks were impermeable to all gases andvapors, except for water. This means that even he-lium, the hardest gas to block off, cannot passthrough the membranes, whereas water vapor wentthrough with no resistance. Now the same teamhas tested the effectiveness of the graphene mem-branes as filters for liquid water. The results,which appear in the journal Science, show that thegraphene rapidly and accurately filters out all saltsexcept those that are smaller than nine Angstroms.7

(Ten Angstroms is equivalent to a billionth of ameter.) The researchers now plan to control thegraphene mesh size and reduce it below nineAngstroms to filter out even the smallest salts inseawater. According to Dr. Irina Grigorieva, a co-author of the study, “Our ultimate goal is to make afilter device that allows a glass of drinkable watermade from seawater after a few minutes of hand

TRENDS E-MAGAZINE APRIL 2014 PAGE 5

pumping. We are not there yet but this is no longerscience fiction.”

� � �

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1. For a more comprehensive look at graphene, visitthe Graphene Information website at:http://www.graphene-information.com/who-discovered-graphene/

2. JOURNAL OF MATERIALS CHEMISTRY, June 7, 2012,“Highly Efficient Electrolytic Exfoliation of Graphiteinto Graphene Sheets Based on Li Ions Intercalation-Expansion-Microexplosion Mechanism,” by Hui Huang,Yang Xia, Xinyong Tao, Jun Du, Junwu Fang, YongpingGan, and Wenkui Zhang. © 2012 by Royal Society ofChemistry. All rights reserved. http://pubs.rsc.org/en/Content/ArticleLanding/2012/JM/C2JM00092J - !divAbstract

3. APPLIED PHYSICS LETTERS, February 13, 2012, “Draw-ing Graphene Nanoribbons on SiC by Ion Implantation,”by S. Tongay, M. Lemaitre, J. Fridmann, A.F. Hebard, B.P.Gila, and B.R. Appleton. © 2012 by American Instituteof Physics. All rights reserved.http://scitation.aip.org/content/aip/journal/apl/100/7/10.1063/1.3682479

4. JOURNAL OF PHYSICS: CONFERENCE SERIES, Vol. 352,Conference 1, 2012, “Microorganism Mediated Synthe-sis of Reduced Graphene Oxide Films,” by Y. Tanizawa,et al. © 2012 by American Institute of Physics. All rightsreserved. http://iopscience.iop.org/1742-6596/352/1/012011

5. PHYSICAL REVIEW X, January - March 2014, Vol. 4, Iss.1, “Dirac Cones, Topological Edge States, and NontrivialFlat Bands in Two-Dimensional Semiconductors with aHoneycomb Nanogeometry,” by E. Kalesaki, C. Delerue,C. Morais Smith, W. Beugeling, G. Allan, and D. Van-maekelbergh. © 2014 by American Physical Society. Allrights reserved.http://journals.aps.org/prx/abstract/10.1103/PhysRevX.4.011010

6. ACS NANO, February 28, 2012, “Graphene: Corrosion-Inhibiting Coating,” by Dhiraj Prasai, Juan Carlos Tu-berquia, Robert R. Harl, G. Kane Jennings, and Kirill I.Bolotin. © 2012 by American Chemical Society. Allrights reserved.http://pubs.acs.org/doi/abs/10.1021/nn203507y

7. SCIENCE, February 14, 2014, “Precise and UltrafastMolecular Sieving Through Graphene Oxide Mem-branes,” by R.K. Joshi, P. Carbone, F.C. Wang, V.G.Kravets, Y.Su, I.V. Grigorieva, H.A. Wu, A.K. Geim, andR.R. Nair. © 2014 by American Association for the Ad-vancement of Science. All rights reserved.http://www.sciencemag.org/content/343/6172/752.abstract

April 2014 Trend #6 Resource List:

Trends: Volume 11, Number 4. April 2014.

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