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1、One DimensionalNanomaterials CarbonNanotubes Reporter Teammates WanjunWuYuanheWangBinbinYangYongzhu 1 1 4 2 3 Outline Introduction StructureandProperties Preparation Applications Introduction SumioIijima Carbonnanotubes CNTs wasfirstdiscoveredbyIijimain1991 CNTs rollingupathingraphenesheet CNTs SWCN
2、Ts MWCNTs ProductionMethods 1 Arc dischargemethod2 LaserVaporizationmethod3 ChemicalVaporDeposition CVD Preparation CVDmethodshavebeensuccessfullyappliedinmakingcarbonnanotubes Thegrowthprocesswiththismethodinvolvesheatingacatalystmaterialtohightemperaturesinatubefurnaceandflowingahydrocarbongasthro
3、ughthetubereactorforaperiodoftime Materialsgrownoverthecatalystarecollecteduponcoolingthesystemtoroomtemperature parameters hydrocarbons catalysts suchastransition metalnanoparticlesgrowthtemperature Leftdiagram basegrowthmode Rightdiagram tipgrowthmode CVDgrowthmechanism Process Dissociationofhydro
4、carbonmoleculescatalyzedbythetransitionmetal Dissolutionandsaturationofcarbonatomsinthemetalnanoparticle Precipitationofcarbonfromthesaturatedmetalparticleleadstotheformationoftubularcarbonsolidsinsp2structure GrowthmechanismofacarbonnanotubeatanopenendbytheabsorptionofC2dimersandC3trimers inblack r
5、espectively TheadsorptionofaC2dimeroraC3trimerattheactivedanglingbondedgesitewilladdonehexagontotheopenend Tubuleformationisfavoredoverotherformsofcarbon becauseatubecontainsnodanglingbondsandthereforeisinalowenergyform Schematicexperimentalsetupsforothertwonanotubegrowthmethods Single wallednanotub
6、esgrownbylaserablation StructureandProperties Theuniquenessofthenanotubearisesfromitsstructureandtheinherentsubtletyinthestructure whichisthehelicityinthearrangementofthecarbonatomsinhexagonalarraysontheirsurfacehoneycomblattices Thehelicity localsymmetry alongwiththediameter whichdeterminesthesizeo
7、ftherepeatingstructuralunit introducessignificantchangesintheelectronicdensityofstates andhenceprovidesauniqueelectroniccharacterforthenanotubes WetSpinning Anaqueoussuspensionofcarbonnanotubes stabilizedbyasurfactant isinjectedintoaflowingsolutionofpolyvinylalcoholwhichcausesthefibertocoagulate Iti
8、sthenremovedfromthebathandwashedtoremoveexcesspolymer OrganizationintoFibers DrySpinning Dryspinningfromcarbonnanotubeforests a Atypical forest ofmultiwallcarbonnanotubesgrownfromasubstrate b Photographofthespinningofacarbonnanotubefiberfromaforestofmultiwallnanotubes a PictureofaSWNTsforest b SEMim
9、ageoftheSWNTsforestledge c HRTEMimageofSWNTs d AlargeareaTEMimage e SEMimageofSWNTcylindricalpillars OrganizationonSurfaces VacuumMicroelectronics Electronfieldemissionmaterialshavebeeninvestigatedextensivelyfortechnologicalapplications suchasflatpaneldisplays electrongunsinelectronmicroscopes micro
10、waveamplifiers EnergyStorage rechargeablelithiumbatteries HydrogenStorage FilledComposites reinforcementsinhighstrength lightweight highperformancecomposites suchasspacecraftandaircraftbody NanoprobesandSensors suchashighresolutionimaging nano lithography nanoelectrodes drugdelivery sensorsandfielde
11、mitters Templates fabricateone dimensionalnanowires Applications Cathode RayLightingElements Demonstrationfieldemissionlightsourceusingcarbonnanotubesasthecathodes Left Schematicofaprototypefieldemissiondisplayusingcarbonnanotubes Right Aprototype4 5 fieldemissiondisplayfabricatedbySamsungusingcarbo
12、nnanotubes FlatPanelDisplay c Stress strainrelationshipobservedduringthetension compressiontestingofthenanotube epoxycomposite thecurvethatshowslargerslope bothonthetensionandcompressionsidesofthestress straincurve belongstothenanotubeepoxycomposite Itcanbeseenthattheloadtransfertothenanotubeishighe
13、rduringthecompressioncycle seenfromthedeviationofthecompositecurvefromthatofthepureepoxy becauseintensiontheindividuallayersofthenanotubesslidewithrespecttoeachother Resultsfromtheopticalresponseofnanotube dopedpolymersandtheiruseinOrganicLightEmittingDiodes OLED TheconstructionoftheOLEDisshowninthe
14、schematicof top ThebottomfigureshowsemissionfromOLEDstructures Nanotubedopingtunestheemissioncolor WithSWNTsinthebufferlayer holesareblockedandrecombinationtakesplaceinthetransportlayerandtheemissioncolorisred Withoutnanotubespresentinthebufferlayer theemissioncolorisgreen UseofaMWNTasanAFMtip Atthe
15、centeroftheVaporGrownCarbonFiber VGCF isaMWNTwhichformsthetip TheVGCFprovidesaconvenientandrobusttechniqueformountingtheMWNTprobeforuseinascanningprobeinstrument MWCNTsastemplates Theleft handfigureisaschematicthatshowsthefillingoftheemptyone dimensionalhollowcoreofnanotubeswithforeignsubstances a S
16、howsaHRTEMimageofatubetipthathasbeenattackedbyoxidation thepreferentialattackbeginsatlocationswherepentagonaldefectswereoriginallypresent arrows andservestoopenthetube b TEMimagethatshowsaMWNTthathasbeencompletelyopenedbyoxidation c TEMimageofaMWNTwithitscavityfilleduniformlywithleadoxide Thefillingwasachievedbycapillarity Thankyou
