Honeycomb Carbon A Review of Graphene 石墨烯综述(2)

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HoneycombCarbon:AReviewofGrapheneMatthewJ.AllenisagraduatestudentintheKanerlaboratoryattheUniversityofCalifornia,LosAngeles(UCLA).HereceivedhisB.S.inphysicsatRiceUniversity,whereheresearchedcarbonnanostructuresinthelaboratoriesofRichardSmalleyandRobertCurl.

VincentC.TungisagraduatestudentintheYanglaboratorycoadvisedbyProf.KanerattheUniversityofCalifornia,LosAngeles(UCLA).HereceivedhisM.S.inchemistryfromtheNationalTsing-HuaUniversityinHsinchu,Taiwan.Hispreviousworkwasonthephotochemistryoforganiclightemittingdiodes(OLEDs).

singlelayers.Totalorganicsyntheseshavebeensizelimitedbecausemacromoleculesbecomeinsolubleandtheoccur-renceofsidereactionsincreaseswithmolecularweight.36Substrate-basedgrowthofsinglelayersbychemicalvapordeposition(CVD)orthereductionofsiliconcarbidereliesontheabilitytowalkanarrowthermodynamictightrope.40Afternucleatingasheet,conditionsmustbecarefullycontrolledtopromotecrystalgrowthwithoutseedingad-ditionalsecondlayersorforminggrainboundaries.

Despitetremendousprogresswithalternatives,mechanicalexfoliationwithcellophanetapestillproducesthehighestqualitygraphene akesavailable.Thisfactshouldnot,however,dampenanyinterestfromchemists.Onthecontrary,therecenttransitionfromtheconsiderationofgrapheneasa“physicstoy”toitstreatmentasalargecarbonmacromoleculeoffersnewpromise.Yearsofcarbonnano-tube,fullerene,andgraphiteresearchhaveproducedamyriadofchemicalpathwaysformodifyingsp2carbonstructures,45-50whichwillundoubtedlybeadaptedtofunctionalizeboththebasalplaneofgrapheneanditsreactiveedges.Thisnotonlypromisestodeliverhandlesforexploitinggraphene’sintrinsicpropertiesbutalsoshouldtoleadtonewpropertiesaltogether.Thisreviewwilldiscussthe eldofgraphenefromamaterialschemistrystandpoint.Afterabriefhistoryofthetopic,theexcitingprogressmadesince2004,inboththeproductionofgrapheneanditsimplementationindevices,

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RichardB.KanerreceivedaPh.D.ininorganicchemistryfromtheUniversityofPennsylvaniain1984.AftercarryingoutpostdoctoralresearchattheUniversityofCalifornia,Berkeley,hejoinedtheUniversityofCalifornia,LosAngeles(UCLA),in1987asanAssistantProfessor.HewaspromotedtoAssociateProfessorwithtenurein1991andbecameaFullProfessorin1993.ProfessorKanerhasreceivedawardsfromtheDreyfus,Fulbright,Guggenheim,andSloanFoundations,aswellastheExxonFellowshipinSolidStateChemistryandtheBuck-WhitneyResearchAwardfromtheAmericanChemicalSocietyforhisworkonrefractorymaterials,includingnewsyntheticroutestoceramics,intercala-tioncompounds,superhardmaterials,graphene,andconductingpolymers.

willbediscussed.Forathoroughdiscussionfocusedonthephysicsofgraphene,seerefs10,11,51,and52.

2.BriefHistoryofGraphene

Tounderstandthetrajectoryofgrapheneresearch,itisusefultoconsidergrapheneassimplythefewestlayerlimitofgraphite.Inthislight,theextraordinarypropertiesofhoneycombcarbonarenotreallynew.Abundantandnaturallyoccurring,graphitehasbeenknownasamineralfornearly500years.Eveninthemiddleages,thelayeredmorphologyandweakdispersionforcesbetweenadjacentsheetswereutilizedtomakemarkinginstruments,muchinthesamewaythatweusegraphiteinpencilstoday.Morerecently,thesesamepropertieshavemadegraphiteanidealmaterialforuseasadrylubricant,alongwiththesimilarlystructuredbutmoreexpensivecompoundshexagonalboron

Figure1.Singlelayergraphenewas rstobservedbyGeimandothersatManchesterUniversity.Hereafewlayer akeisshown,withopticalcontrastenhancedbyaninterferenceeffectatacarefullychosenthicknessofoxide.(ReprintedwithpermissionfromScience(),ref2.Copyright2006AmericanAssociationfortheAdvancementofScience.)