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Graphene:FromfundamentaltofutureapplicationsContentIntroductiontographene.PotentialapplicationofgrapheneConclusionsGrapheneisaone-atom-thickplanarsheetofsp2-bondedcarbonatomsthataredenselypackedinahoneycombcrystallatticeThename‘graphene’comesfromgraphite+-ene=grapheneHighresolutiontransmissionelectronmicroscopeimages(TEM)ofgrapheneIntroductiontographeneMolecularstructureofgrapheneA.K.Geim&K.S.Novoselov.Theriseofgraphene.NatureMaterialsVol.6,183-191(2007).IntroductionIntroduction-Electronicproperties-Thermalproperties-Mechanicalproperties-Opticalproperties-Relativisticchargecarriers-AnomalousquantumHalleffectPropertiesofgrapheneIntroductionPropertiesofgraphene-HighYoung’smodulus(~1,100Gpa)Highfracturestrength(125Gpa)-Monolayergrapheneabsorbsπα≈2.3%ofwhitelight(97.7%transmittance),whereαisthefine-structureconstant.MechanicalpropertiesOpticalpropertiesArepresentationofadiamondtipwithatwonanometerradiusindentingintoasingleatomicsheetofgraphene(Science,321(5887):385)-Grapheneisasthestrongestmaterialevermeasured,some200timesstrongerthanstructuralsteelBriefhistoryofgrapheneThetermgraphenefirstappearedin1987todescribesinglesheetsofgraphiteasoneoftheconstituentsofgraphiteintercalationcompounds(GICs).Largergraphenemoleculesorsheets(sothattheycanbeconsideredastrueisolated2Dcrystals)cannotbegrowneveninprinciple.Inthe1930s,LandauandPeierls(andMermin,later)showedthermodynamicsprevented2-dcrystalsinfreestate,anarticleinPhysicsTodayreads:Fundamentalforcesplaceseeminglyinsurmountablebarriersinthewayofcreating[2Dcrystals]...Nascent2Dcrystallitestrytominimizetheirsurfaceenergyandinevitablymorphintooneoftherichvarietyofstable3Dstructuresthatoccurinsoot.Butthereisawayaroundtheproblem.Interactionswith3Dstructuresstabilize2Dcrystalsduringgrowth.Soonecanmake2Dcrystalssandwichedbetweenorplacedontopoftheatomicplanesofabulkcrystal.Inthatrespect,graphenealreadyexistswithingraphite...OnecanthenhopetofoolNatureandextractsingle-atom-thickcrystallitesatalowenoughtemperaturethattheyremaininthequenchedstateprescribedbytheoriginalhigher-temperature3Dgrowth.”In2004:AndreGeimandKostyaNovoselovatManchesterUniversitymanagedtoextractsingle-atom-thickcrystallites(graphene)frombulkgraphite:Pulledoutgraphenelayersfromgraphiteandtransferredthemontothinsilicondioxideonasiliconwaferinaprocesssometimescalledmicromechanicalcleavageor,simply,theScotchtapetechnique.Since2004,anexplosionintheinvestigationofgrapheneintermofsynthesis,characterization,propertiesaswellasspecificalpotentialapplicationwerereported.Potentialapplicationofgraphene-Singlemoleculegasdetection-Graphenetransistors-Integratedcircuits-TransparentconductingelectrodesforthereplacementofITO-Ultracapacitors-Graphenebiodevices-Reinforcementforpolymernanocomposites:Electrical,thermallyconductivenanocomposites,antistaticcoating,transparentconductivecomposites..ectElectrical,thermallyconductivenanocompositesNature,Vol.442,20,July(2006)TransparentconductingelectrodesReinforcementforpolymernanocompositesACSNano,2009,3(12),pp3884–3890CONCLUSIONGraphenehasaninterestinghistory,butmanynowwonderaboutitsfuture.Thesubjectofconsiderablescholarlydebate,itdoesseemreasonabletoassertafewthingslookingahead:First,thequalityandavailabilityof“synthetic”graphenewillcontinuetoimprove.Whetherhighqualitymaterialcomesintheformofanalternativechemicalroutetothecompleteexfoliationofgraphiteorfromoptimizationofthethermalprocessesrequiredforsubstrate-basedmethods,thereisnosignthatsynthetictechniquesarenearingtheirupperlimit.Thismeansthatdeviceengineerswillhaveampleaccesstoimprovedmaterialsfordevelopingnovelstructuresandfindingwaystointegrategrapheneintopresent-dayelectronicdevices.Second,chemicalmodificationofgraphene’sbasalplaneoritsedgeswillsubstantiallyinfluencegraphene-baseddevices.Forelectronicapplications,onecanimaginetheattachmentoffunctionalgroupsaimedatself-assemblyofsimplecircuitsortheincorporationofchemicaldopantstolimitleakagecurrentunderzerogatebias.Forsensors,lockand-keytypebindingsitescouldprovideselectivesensitivitytoawidevarietyofanalytes.Thesemightincludechemicalwarfareagentsorevenbiologicalspecies.Third,industrialuseofgrapheneasatransparentconductorcouldhavehugeimplicationsforthesolarindustry.Assyntheticroutesimprove,theprospectofreplacingITOwithalow-costcarbon-basedcoatingseemsfeasible.Thiswouldnotonlyremovesignificantuncertaintyabouttheavailabilityandcostofindiumbutalsoenablenonevaporativeroll-torollprocessingoftransparentconductors.