The Sub­stance That Will Shape Our Fu­ture

Re­searchers have cre­ated a sub­stance from in­di­vid­ual car­bon atoms that could change the world: graphene. It’s be­ing hailed as the ma­te­rial that can cat­a­pult us into a new era— even though it shouldn’t ex­ist at all…

iD magazine - - Contents -

An in­cred­i­ble ma­te­rial that shouldn’t even ex­ist

“GRAPHENE’S PROP­ER­TIES ARE UNIQUE— SO DIS­TINC­TIVE, IN FACT, THAT THERE IS NO COM­PA­RA­BLE SUB­STANCE IN THE WHOLE OF SCI­ENCE.” Michael Strano, Mas­sachusetts In­sti­tute of Tech­nol­ogy (MIT)

How do you make some of the most pres­ti­gious physi­cists of our time jump for joy? Very eas­ily. Talk about per­haps the most ground­break­ing dis­cov­ery made in the last 100 years: graphene—the first two-di­men­sional ma­te­rial in the world. It’s con­sid­ered a mir­a­cle sub­stance and, for many ex­perts, the start point for rad­i­cally chang­ing our lives in the fu­ture.

The odd part: Graphene con­sists of noth­ing more than car­bon, which is ut­terly ubiq­ui­tous on this planet— for in­stance, it’s in ev­ery­thing from the air and vi­ta­mins to pen­cil leads. But the fact is that we still know very lit­tle about this sub­stance, which is in­volved in ap­prox­i­mately 90% of all chem­i­cal com­pounds. Only in re­cent years have we got­ten a rudi­men­tary glimpse into its unique ca­pa­bil­i­ties: “Graphene em­bod­ies an un­usu­ally large num­ber of su­perla­tives,” says Jur­gen Smet, a nanoph­ysist at the Max Planck In­sti­tute for Solid State Re­search. It can con­duct heat and sup­ply en­ergy more ef­fec­tively than cop­per; it’s trans­par­ent, yet it also ab­sorbs light. What’s more, though it’s over 266,000 times thin­ner than a hu­man hair, it’s also stronger than con­crete; it’s more than 200 times stronger than steel, it’s ex­tremely flex­i­ble, and it’s so dense that even he­lium—the small­est no­ble gas— can’t pass through it. To Klaus von Kl­itz­ing, win­ner of the 1985 No­bel Prize for Physics and a pro­fes­sor at the Max Planck In­sti­tute for Solid State Re­search, graphene is re­ally a “su­per­hero among the ma­te­ri­als.” It is hardly lim­ited in its ca­pa­bil­i­ties. “Depend­ing on its form, graphene is able to de­velop dif­fer­ent pow­ers.” But what makes this sub­stance so spe­cial, and how do sci­en­tists want to ap­ply it to shape our fu­ture?

HOW CLEAR TAPE HAS CHANGED THE WORLD

Un­til Oc­to­ber 22, 2004, graphene did not have a good stand­ing in the sci­en­tific com­mu­nity. It was viewed as a sub­stance that couldn’t ex­ist. The rea­son for this view: graphene’s spe­cial struc­ture, which con­sists of in­di­vid­ual car­bon atoms ar­ranged to­gether to form uni­form hexagons. Be­cause graphene is com­posed of a sin­gle layer of atoms—and so it is no thicker than one car­bon atom—it is re­ferred to as a two-di­men­sional sub­stance. The prob­lem: Physics con­sid­ers 2- D ma­te­ri­als un­sta­ble, there­fore graphene was thought to be phys­i­cally im­pos­si­ble. It was an un­prece­dented mis­judg­ment that was even­tu­ally ex­posed by No­bel Prize win­ners Kon­stantin Novoselov and An­dre Geim in the fall of 2004— in an ex­tremely sim­ple way. In fact, these two Uni­ver­sity of Manch­ester re­searchers cre­ated the first sta­ble 2-D ma­te­rial in the world us­ing lit­tle more than a strip of ad­he­sive tape and a chunk of graphite—a coal-like ma­te­rial that’s also found in pen­cils. To make a sin­gle layer of graphene from graphite, the sci­en­tists sim­ply pressed a length of ad­he­sive tape

against the block of graphite and then pulled it off again. This re­sulted in a very thin—but still mul­ti­lay­ered— strip of car­bon re­main­ing on the tape. To re­move more lay­ers, they placed the seg­ment of car­bon-cov­ered tape against a sil­i­con plate that had been coated with pho­tore­sist (a ma­te­rial that is sen­si­tive to light)—and then pulled the tape off again. The re­sult: high-qual­ity sta­ble graphene, and the refu­ta­tion of an al­leged law of na­ture.

HOW HARD IS A FIN­GER­PRINT?

Today graphene is at the cen­ter of a multi­bil­lion- dol­lar mar­ket. How­ever, new meth­ods are nec­es­sary in or­der to cover the rapidly grow­ing de­mand. Now a re­search team from Saar­land Uni­ver­sity may have come up with a solution to this press­ing prob­lem. In a spec­tac­u­lar process, they man­aged to ob­tain the graphene from sweat, which con­tains car­bon com­pounds. Their study sub­jects were asked to leave fin­ger­prints on a film that was baked in a vacuum oven at 1,300°F. The re­sult: graphene. They called this manufacturing pro­ce­dure chem­i­cal va­por de­po­si­tion. In the near fu­ture, this method should make it pos­si­ble to ob­tain graphene on a large scale from any liq­uid that con­tains car­bon com­pounds (such as ace­tone). The ad­van­tage: Such liq­uids are widely avail­able and rel­a­tively in­ex­pen­sive. So mass pro­duc­tion of the pre­cious ma­te­rial should soon be within reach.

REV­O­LU­TION FROM OUT OF A PEN­CIL

Even though graphene is con­sid­ered a ma­te­rial of the fu­ture, it’s al­ready start­ing to be used. The Uk-based com­pany Graphene Light­ing is now on the verge of bring­ing a graphene light­bulb to the mar­ket. This prod­uct is sup­posed to “use less en­ergy than the en­ergy-ef­fi­cient LED tech­nol­ogy, have lower pro­duc­tion costs, and be pro­duced with sus­tain­able ma­te­ri­als,” says Colin Bai­ley, deputy pres­i­dent of the UK’S Uni­ver­sity of Manch­ester. The use of this mir­a­cle sub­stance is still in its in­fancy, but the po­ten­tial tech­ni­cal in­no­va­tions al­ready sound like the stuff of sci­ence fic­tion films. In 2014, the South Korean tech gi­ant Sam­sung re­port­edly filed for a patent for the man­u­fac­ture of trans­par­ent film-thin graphene com­puter mod­ules that can serve as a phone as well as a high-res­o­lu­tion touch­screen—and can be folded or rolled.

Graphene has another im­pres­sive prop­erty: It is trans­par­ent, yet at the same time it’s light-ab­sorb­ing—which makes it per­fect for cap­tur­ing so­lar en­ergy via a spe­cial win­dow glass.

Re­searchers at Spain’s In­sti­tute of Pho­tonic Sciences have achieved an ef­fi­ciency level of about 50% in so­lar cells made with graphene, and 60% should be pos­si­ble—dizzy­ing val­ues that are twice as ef­fi­cient as cur­rent com­mer­cially avail­able so­lar cells. But this is far from all the ca­pa­bil­i­ties of the new won­der ma­te­rial. Physi­cists are de­vel­op­ing ways to har­ness the con­duc­tiv­ity of graphene in or­der to rev­o­lu­tion­ize our en­ergy tech­nol­ogy. But per­haps the most sig­nif­i­cant way to use graphene has been de­vel­oped by the Amer­i­can de­fense con­trac­tor Lock­heed Martin: a graphene fil­ter for re­mov­ing sodium and chlo­rine from water. To trans­form graphene into a salt fil­ter, the su­per­dense ma­te­rial is fur­nished with holes only big enough to al­low water to pass through; other sub­stances (drug residue, im­pu­ri­ties) are blocked. This fil­ter is 500 times thin­ner than the thinnest pre­vi­ously de­vel­oped salt fil­ters and re­quires only about 1% of the en­ergy to make sea­wa­ter potable. This tech­nique has al­ready been uti­lized in de­sali­na­tion plants. Projects like these have made graphene one of the most promis­ing dis­cov­er­ies of the 21st century, and on­go­ing re­search should yield un­told ben­e­fits for the fu­ture for hu­man­ity.

“FLEX­I­BLE AND TRANS­PAR­ENT TOUCH­SCREENS ARE ONE OF THE EAR­LI­EST AP­PLI­CA­TIONS OF GRAPHENE.” Klaus von Kl­itz­ing, Max Planck In­sti­tute for Solid State Re­search, Stuttgart, Ger­many

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