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AnIntroductiontoNanomaterialsTel:62756773Email:yanli@chem.pku.edu.cn—1.2.3.4.5.6.WhymovingintonanoworldA.Intellectualdrive•MiniaturizationisofinterestLessspace,faster,lessmaterials,lessenergy•Moreimportant:Novelproperties/phenomena/process-Newstructureandfunctions;EngineeringbeyondnatureUnityandgenerality-Atthebuildingblocksofallnatural/artificialthings,systemsMostefficientlengthscaleformanufacturing-LessenergythanforsubatomicormacroscopicTranscendenteffects:attheconfluenceofsteams-S&T;Living/non-living;interdisciplinary;RelevanceareasB.Promiseofnanotechnology(exampleofsocietalimplications)Knowledgebase:bettercomprehensionofnature,lifeAnewworldofproducts:-$1trillion/yin10-15years-Materialsbeyondwhatchemistrycando:$340B/yin10yearsformaterialsandprocessing,(estimationbyindustrygroup)-Electronnicsin10-15years:$300B/Yforsemiconductorindustry,timesmoreforglobalintegratedcircuts(estimationbySIA)-Pharmaceuticsin10-15yearsabouthalfofproductionwilldependonnanotechnology,affectingabout$180B/Y–Chemicalplantsin10-15years:nanostructuredcatalystsinpetroleumandchemicalprocessingabout$100B/Y–Aerospace:about$70B/Yin10years–Tools(measurement,simulation)--$22B/Yin10yImprovedhealthcare:extendlife-span,itsquality,humanphysicalcapabilities(-$31Bintoolsforhealthcarein10years)Sustainability:agriculture,water,energy(-45B/yin10years)materials,environment,exitinglightingenergyreduction–10%or$100B/YNoblePrizelaureate,Feynman,inhis1960article“There’splentyroomatthebottom”discussedtheadvantagesthatcouldbeprovidedbycontrollingthestructureofmatteratombyatom.Forexample,hepointedoutthatifabitofinformationrequiresonly100atoms,thenallthebookseverwrittencouldbestoredinacubewithsides0.02inlong.¾¾1857¾1861¾1962(Kubo)¾¾1985KrotoSmalleyC60¾19907¾1994MRSSTMXeonNiCOironatomoncopper(1)(2)(3)(4)(5)(6)(7)(8)……999“”—9—“”9—()……()…………SCHEME:SolventEvaporationfromNanocrystalDispersiononaSubstrate:EntropyDrivestheOrderingofHardSpheresWhentheParticleVolumeFractionExceedsaCriticalValue,0.49TEMimagesofatwo-dimensionalhcpsilvernanocrystalsuperlattice(left),andthe2-DFouriertransformpowerspectrunoftheimageJ.Phys.Chem.B1998,102,8379-8378TEMmicrographofmonolayerfilmsof3.7nmAuclustersSelf-assemblyofaLCN(ScienceV273,1690-1693,1996)AssembleandcompressnanoparticlesbyL-BfilmsTEMimagesofcompressedfilmsconsistingofAgparticles,27Aindiameter(A)separatedby6A,(B)by12A(Science,277,1978-1980,1997)DNAAlivisatosetal.,Nature,1996,382,609C.A.Mirkinetal.,Nature,1996,382,607()1.—Kubo2.3.4.1.1)(Kubo)δ=(4/3)(EF/N)∝V-1δ,NEFVδ∝1/d32)¾¾¾¾1337K2nm600K2.204080993×1044×1032.5×1023010421%d/nm3.Ec=e2/2CVNumberofElectrons“CoulombStaircase”atroomtemperatureinaself-assembledmolecularnanostructure,Science,V272,1323-1325electronVEcVe/C(e2/2C)kbT1nm4.1.…-…2.1)ChemicalVaporDeposition,CVD2060JohnMBlocherJrVaporDepositionPVDCVDCVD♣CVD♣III-V♣CH4C+H2600-1000ºCSiH4Si+H2600-800ºCNi(CO)4Ni+CO140-240ºC3SiH4+4NH3Si3N4+12H2750ºCCH4C()+H2800-1000ºCPlasmaEnhancedCVDLaserInducedCVDCH4C()+H2800-1000ºCPlasmaEnhancedCVDLaserInducedCVDMOCVDZnOandSnONanobeltsSCIENCEVOL2919MARCH2001SiO2Nanowire2hydrothermalSolvothermalSynthesis1996¾¾¾¾¾3)sol-gel45Template-directedSynthesisofnanomaterialsCdSAAO500N2Cd(Ac)2CH3CSNH2CdSnanowiresproducedinAAOtemplateswiththediameterof20nm(a),30nm(b,c),and50nm(d),respectively.a2µmb500nmc150nmd100nmTheTEMimagesofAgnanowiresformedinAAOmembranewithdifferentporediameters,(a)and(b),20nm;(c)and(d)50nm.b500nma1.2µmc100nmd200nmCdSCdS50nmd0d1.sars1sars22.1)2)3)d=2π(B/∆ω)1/23.X-d=kλ/βcosθ3.CdS°.1Cd(Ac)2/mmol3.001.500.301.65ABCDTAA/mmol3.301.650.331.50CH3CSNH2+2H2O=CH3COONH4+H2SCd(Ac)2+H2S=CdS+2HAc(TEM)JEOLJEM-200CX200kVX(XRD)RigakuDmax-2000XX(CuKα40kV)(FL)Hitachi4500ShimadiuUV-2101PC1CdSTEMHRTEMimageofCdSnanowire.2CdSXScherrer:D=kλ/βcosθkCdS1[27]λxθβCdSA8.72nm7nmB4.99nm5.4nmC6.13nm6.5nmD3.97nm4.4nmXRDabsorptionParticlesizegrainsize2.482.522.562.62eVCdS3CdS400450500550600650CDBAIntensityWavelength(nm)4CdS310nm5CdS345nmScanningProbeMicroscopy(ScanningProbeMicroscopy)STMVIIV·exp(-2kZ)ZkZIZIZIRZ·πφScanningForceMicroscopyC60STMJ.Houetal.NatureVol40918January2001J.W.G.Wildoeretal.,NATUREVOL3911JANUARY1998AFMExamplesofNanotechnologyApplication•Giantmagnetoresistanceinmagneticstorageapplication•Nanostructuredcatalysts•Drugdeliverysystems•Nanocomposites:nanoparticlesreinforcedpolymers•Nanoelectronicdevices•LEDlightningbreakthroughsfromnanotechnology•Bio-chemdetectionofcontaminantsorviruses•Waterpurificationanddesalinizatiojn“Buildingblocks”AtomsNanoparticlesNanowireLayerSynthesisAssemblyNanostructuresDispersionandcoatingConsolidatedmaterialsinterfacialmaterialsFunctionalnanodevicesSingleWalledCarbonNanotubesHRTEMimagesofcarbonnanotubesSTMimageofasingle-walledcarbonnanotubeAFMimageofSWNTsandSWNTbundlesMethodsforPreparationofSWNTs•Arc-Charge•LaserAblation•ChemicalVaporDeposition1200CFurnaceNd:YAGLaser500torrArCtarget(2%Ni:Co)ColdfingerascollectorLaserAblation1200CFurnacecatalystFeedgasFeedStockGas:CO,CH4,etc.Catalyst:Fe,Mo,Ni,Coetc.Temperature:700–1100ºCChemicalVaporDepositi