晶种生长法制备不同形貌的金纳米颗粒

晶种生长法制备不同形貌的金纳米颗粒

水生生物区系、ph检查和母性可接近纳米遗传因素，而非正合金属钠的研究领域更为丰富。镜头是明亮的，检察官是明亮的，信息是明亮的，质量分析是明亮的。预算和非预算控制部分从预算控制中继承，数量从100米到1.12米不等。更不用说，这是一个预算控制。金属单胞的数量是分散的，这是一个循环。Thispaperpresentsourrecentdevelopmentofasimpleandefficientmethodoffabricatinggoldnanoparticleswithdifferentpatterns.SphericalgoldnanoparticlesareobtainedusingNa3-citrateandNaBH4asreducers.Thesizeofnanoparticlescanberegulatedbycontrollingtheamountofthereducers.Usingseed-mediatedsolutiongrowthmethod,goldnanoparticleswithdifferentshapes,suchasstar,shuttleandstickshapes,canbeobtained.Thestarandtheshuttle-shapedgoldnanoparticlesarefabricatedbycontrollingtheamountofgrowthsolution,whereasstick-shapedgoldnanoparticlescanbeobtainedbycontrollingthecomponentofthegrowthsolution.Goldnanoparticleswithdifferentpatternsarecharacterizedbytransmissionelectronmicroscopy(TEM).Theresultsillustrategrowthprocessofthegoldnanoparticleswithdifferentmorphologies.AbsorptionspectroscopyandRamanspectroscopymeasurementsareperformedtodemonstratedifferentopticalpropertiesofthegoldnanoparticleswithdifferentsizesandmorphologies.Duringthegrowthprocess,theshiftsofabsorptionspectraarerelatedtodifferentsizesandmorphologiesofthegoldnanoparticles.Ramanspectroscopymeasurementresultsindicatethatthestar-shapedgoldnanoparticlesexhibitmorepromisingopticalfeaturesbecauseoftheirspecialpatterns.Theuniquecontributionofthispaperisthat,withtheproposedmethod,goldnanoparticleswithdifferentpatternscanbefabricatedusingthesameprocess.Inthisway,differentperformancesofgoldnanoparticleswithdifferentpatternscanbecomparedunderthesameconditions,suchastemperature,airpressure,noise,etc.Goldnanoparticlesexhibitmagicopticalpropertiesbecauseoftheirlocalizedsurfaceplasmonresonance(LSPR).LSPRcanenhancethelocalelectricfieldaroundthegoldnanoparticles.TheabsorptionspectraandSERSofthegoldnanoparticleschangeduringtheirgrowthprocess.Consideringthatthelocalelectricfieldaroundstar-shapedgoldnanoparticlesislarge,thesegoldnanoparticlescanbetterenhancetheRamansignalthanthosewithotherpatterns.SERSofsphericalandstar-shapedgoldnanoparticleswascharacterizedinthisstudy.TheresultsindicatethatthepatternsofgoldnanoparticlesarecorrelatedwithLSPR.DuetouniqueadvantagesoflargelyenhancingRamansignal,thegoldnanoparticlescanbeappliedtothedesignofmicro-sensorsforvariouschemicalandbiologicalapplications.1Methodology1.1which-关于so内部sosso-soin-soin-soin-soin-soin-soin-soin-soin-soin-soin-soin-soin-soin,soin-soin,veThesodiumcitratereducingmethodwasemployedinthisstudy.Theproceduresforpreparingsmall-sizegoldnanoparticlesaredescribedbelow.Firstly,100mLof0.25mmol/Lauricchloride(analyticalreagent(AR))solutionwasputintoa250mLflask,andthenheatedtoboilingbyconstanttemperaturewaterbath(MPL-HWS).Secondly,3.5mLof1%sodiumcitrate(AR)wasaddedrapidlyintoan800r/minstirringsolutionwhileheatingcontinued.Multifunctionalmagneticstirrer(MPL-CJ-88)wasusedtostirandheatthesolution.Around3minthereafter,thesolutionturnedtogray,andthentodarkred.Afterheatedforanother15min,thesolutionwascooleddowntoroomtemperature,and18.25MΩdeionizedwater,whichwaspurifiedthroughtheultra-pure(UPR)system,wasaddeduntilthevolumewasbackto100mL.Finally,10nmgoldnanoparticleswereobtained.Theproceduresforpreparinglarge-sizegoldnanoparticleswereslightlydifferentfromthoseforsmall-sizegoldnanoparticles.Firstly,100mLof0.25mmol/Lauricchloridesolutionwasputintoa250mLflask,andthenheatedtoboiling.Secondly,1.5mLof1%sodiumcitrate(AR)wasaddedrapidlyintoan800r/minstirringsolutionwhileheatingthesolutioncontinually.Around3minthereafter,thesolutionturnedtogray,andthentodarkred.Afterheatedforanother15min,thesolutionwascooleddowntoroomtemperature.Then,deionizedwaterwasaddeduntilthevolumewasbackto100mL.Finally,50nmgoldnanoparticleswasobtained.Transmissionelectronmicroscope(JEOLJEM-1200EX)wasusedtocharacterizepatternsandsizesofthenanoparticles.ThefabricatedgoldnanoparticleswerecharacterizedbyTEM.Fig.1showstheTEMimagesandpicturesofsphericalgoldnanoparticleswithdifferentsizes.The10nmsphericalgoldnanoparticleswereobtainedbyadding3.5mLsodiumcitrate,asseeninFig.1(a).The50nmsphericalgoldnanoparticleswereobtainedbyadding1.75mLsodiumcitrate,asseeninFig.1(b).Thelightred10nmsphericalgoldsolisshowninFig.1(c),andthedarkredsolationwith50nmgoldnanoparticlesisshowninFig.1(d).Theseresultsdemonstratethatdarkredgoldsolwith10nmsphericalgoldnanoparticlescouldbeobtainedbykeepingthevolumeratioofchloroauricacidtosodiumcitratelessthan1∶3.5.Byreducingtheamountofsodiumcitrate,thepurplegoldsolwith50nmsphericalgoldnanoparticleswasobtained.1.2主要so阶段asin共建soin-shpoged,shponed.Atotalof10mLof0.25mMauricchloridesolutionwasputintoabeaker.Afteradding0.35mLof1%sodiumcitrate,thebeakerwasshockedgentlyfor3min.Then,0.3mLfreshsodiumborohydride(99%)wasaddedtothesolution,whichwasthenshockedfor5min.Aftermaintainingtheprocessfor2h,theseedsolutionwasobtained.Theproceduresforpreparingthegrowthsolutionaredescribedbelow.Atotalof7.28ghexadecylammoniumbromide(AR)and1.36mgsilvernitrate(AR)wereputintoabeaker,whichhad200mLof0.25mMauricchloridesolution.Thebeakerwaskeptat40℃forhalfanhouruntilhexadecylammoniumbromidewasdissolvedcompletely.Afterthesolutionwasshockedfor5min,itturnedintoacleardarkredcolor.Then,0.1mLseedsolutionwasputintoabeaker.Next,0.006,0.6,and6mLof10mMascorbicacidwereputintothreebeakerswith1,10,and100mLgrowthsolution,respectively.Threeportionsofthegrowthsolutionwerefinallyobtained.Thethreeportionsofthegrowthsolutionwerethenputintotheseedsolutionevery30s.Theshuttle-shapedgoldnanoparticleswereobtainedbeforeaddingthesecondportionofthegrowthsolution.Thestar-shapedgoldnanoparticleswereobtainedafteraddingallthethreeportionsandaftermaintainingtheprocessforseveralhours.Thestick-shapedgoldnanoparticlesalltheproceduresofsynthesizingwerethesameasthatofsynthesingstar-shapedgoldnanoparticles,butnosilvernitrateinthegrowthsolution.Fig.2illustratesgoldnanoparticlesobtainedafteraddingeachportionofthegrowthsolutionduringthesynthesisofstar-shapedgoldnanoparticles.Fig.2(a)illustratestheTEMimageofgoldnanoparticlesintheseedsolution,where10nmsphericalgoldnanoparticleswereobtained.Fig.2(b)illustratesthat,afteraddingthefirstportionofthegrowthsolution,50nmshuttle-shapedgoldnanoparticleswereobtained.Afteraddingthesecondportionofthegrowthsolution,smalltipsoccurredonthegoldnanoparticles,asshowninFig.2(c).Owingtotheaeolotropicgrowthmodeofparticles,80nmstar-shapedgoldnanoparticleswereobtained5hafterthethirdportionofthegrowthsolutionwasadded,asshowninFig.2(d).Fig.2(e)showsthatstick-shapedgoldnanoparticleswerefabricatedwhentherewasnosilvernitrateinthegrowthsolution.Theseedsolutionwith10nmsphericalgoldnanoparticleswasred,asshowninFig.2(f).Thebluestar-shapedgoldsolsareshowninFig.2(g).Theaboveresultsdemonstratethatshuttle-shaped,star-shapedandstick-shapedgoldnanoparticlescouldbefabricatedbycontrollingthecomponentsofthegrowthsolution.2影响的神圣迪迪斯运营2.1so阶段案例5aurcctorityagol-soina&shpolega,etizact.uInthisstudy,sphericalgoldnanoparticleswereobtainedusingthereductionmethod,wheresodiumcitratewasusedforreductionandprotection,asshowninFig.3(a).Shuttle-shaped,star-shaped,andstick-shapedgoldnanoparticleswerefabricatedusingtheseed-mediatedsolutiongrowthmethod.Fig.3illustratestheprincipleinsynthesizinggoldnanoparticleswithdifferentpatterns,i.e.,(a)sphericalshape,(b)shuttleshape,(c)starshape,and(d)stickshape.Tosynthesizetheseedsolution,auricchloridewasreducedusingsodiumborohydride.Sodiumcitratewasusedaschelationagenttoobtainastablegoldseedsolution.Thegrowthsolutionincludesaweakreductionascorbicacid,templatehexadecyltrimethylammoniumbromide,auricchloride,andsilvernitrate.Nucleationcontrolisimportantintheseed-mediatedsolutiongrowthmethod.Tomakesurethattherewasnonewcoreformattingduringthegrowthprocess,thefollowingtwooperationswereperformed.Firstly,theweakreductionascorbicacidwasmonitored,suchthatAu3+wasnotreduceduntiltheseedsolutionwasaddedtothegrowthsolution.Secondly,byaddingthreeportionsofthegrowthsolution,theratioofthegoldseedtothegrowthsolutionwascontrolledto1∶10.Differentcomponentsandamountsofthegrowthsolutionleadtodifferentpatternsofgoldnanoparticles.SilvernitratecouldnotbereducedbyaweakreductionascorbicacidunderalowPHvalue.Ag+couldreplacethegoldgrowthparticlesonthegoldseedparticlesurface.Theblockingphenomenonwasthekeyinthesynthesisofthestar-shapedgoldnanoparticles.InFig.3(b),shuttle-shapedgoldnanoparticlesweresynthesizedafterthefirstportionofthegrowthsolutionwasadded.Fig.3(c)showsthatstar-shapedgoldnanoparticleswereobtainedafterthreeportionsofthegrowthsolutionwereadded.Stick-shapedgoldnanoparticleswereobtainedbyaddingthegrowthsolutionwithoutsilvernitrate,asshowninFig.3(e).2.2which-非织造agregactwhich-非织造ssitoritysicece.sipholgachisossicedi标准sicedi标准sipholgachisoThemostimportantfeatureofthemetalnanoparticleabsorptionspectraliesintheirsurfaceplasmonband.Theabsorptionpeaksofsurfaceplasmonresonance(SPR)areexcitedbyfreeelectricconcussion,anddifferentsizesandmorphologiesofgoldnanoparticlesleadtodifferentabsorptionpeaks.TheabsorptionspectrawerecharacterizedbyUV-Visspectrometer(Cary-300).Fig.4showsthattheabsorptionof10nmsphericalgoldnanoparticlespeaksatawavelengthof520nm(seecurve(a)),andthattheabsorptionof50nmsphericalgoldnanoparticlespeaksatawavelengthof530nm(seecurve(b)).Theseresultsagreewiththeelectromagnetictheory,whichstatesthatthelargerthenanoparticlesare,thelongerthewavelengthisinwhichtheabsorptionpeakoccurs.Thewidthofthehalfwavedependsonthesizedistributionofthegoldnanoparticles.Thewiderthehalf-wavewidthis,thewiderthesizedistributionofthegoldnanoparticlesis.TheresultsinFig.4verifythatthesizedistributionof10nmsphericalgoldnanoparticlesissimilartothatof50nmsphericalgoldnanoparticles.Fig.5(a)illustratesabsorptionspectraofthegoldnanoparticleswithdifferentshapes,whichwereobtainedbyaddingthreeportionsofthegrowthsolutionintotheseedsolution.Curve(a)isthespectrumoftheseedsolution.Curve(b)isthespectrumofshuttle-shapedgoldnanoparticlesobtainedbyaddingthefirstportionofthegrowthsolution.Curve(c)isthespectrumofthegoldnanoparticlesobtainedbyaddingthefirstportionofthegrowthsolution.Curve(d)isthespectrumofthestarshapedgoldnanoparticlesobtainedafteraddingthegrowthsolutionthreetimes.Fig.5(b)showstherelationshipbetweenpeakpositionandparticle’sdiameter,whichdemonstratesthered-shiftingoftheabsorptionspectrumastheparticlediameterincreases.Thereasonisthatthenanoparticle’sdiameterisinverselyproportionaltoenergylevelgapoftheadjacentelectronicstates.Thebiggerthediameterofthenanoparticle,thewiderthelevelgapbetweenelectronsonthehighestandlowestorbitals.Lessenergyisneededforelectrontransitionduringthephotochromicprocess.Therefore,theredshiftoccurswhenthenanoparticle’sdiameterincreases.InFig.5(a),curve(a)istheabsorptionspectrumof10nmgoldnanoparticlesintheseedsolution,inwhichtheabsorptionpeakoccurredatawavelengthof520nm.Curve(b)istheabsorptionspectrumof50nmshuttle-shapedgoldnanoparticles,whichwereobtainedbyaddingthefirstportionofthegrowthsolution.Theabsorptionpeakoccurredatawavelengthof620nm,whichhad100nmredshiftwithrespecttothepeakofcurve(a),indicatingthatthesizeofthegoldnanoparticlesisbigger.Thewidthofthehalfwaveofcurve(b)waswider,indicatingthatthesizedistributionofshuttle-shapedgoldnanoparticleswaswider.Curve(c)istheabsorptionspectrumofgoldnanoparticlesobtainedafteraddingthesecondportionofthegrowthsolution.Au3+wasreducedusingascorbicacid.InFig.2(c),thegoldnanoparticlesaresmallerbutnotstillstar-shaped,asseenincurve(c).Therewasabout80nmblueshiftcomparedwithcurve(b),indicatingthatthesizeofthegoldnanoparticlesissmaller.Curve(d)istheabsorptionspectrumofgoldnanoparticlesobtainedafteraddingthethirdportionofthegrowthsolution.Comparedwithcurve(c),curve(d)has80nmredshift,indicatingthatthesizeofthegoldnanoparticlesafteraddingthethirdportionofthegrowthsolutionwasbigger.Theabovecharacterizationresults,whichagreewithFig.2,demonstratethatsphericalgoldnanoparticlesturnedtoirregulardoublecones,andthentotwig-likestar-shapedgoldnanoparticles.TheresultsinbothFig.5andFig.2alsoindicatethattheabsorptionpeaksareshiftingasthemorphologieschangeduringthegrowthprocess.Thedifferentabsorptionspectraofthegoldnanoparticleswithdifferentpatternsmakethegoldnanoparticlesbeappliedtothedesignofopticalsensorswithdifferentwavelengths.Tostudytheopticalpropertiesofgoldnanoparticleswithdifferentshapes,bothsphericalandstarshapedgoldnanoparticlesweretestedinSERS.CrystalvioletwasusedastheprobingmoleculetodetectSERSsignal.Thestepsforpreparingsamplesaredescribedasfollows.Atotalof6mLsphericalandstar-shapedgoldsolswereputinto2mLcentrifugetubes,whichwerecentrifugedat14000r/minfor10minbyhigh-speeddesktopcentrifuge(TGL-16K).Theuppersolutionwithoutnanoparticleswasremoved,andthenrestoredtoitsoriginalvolumeindeionizedwater.Thisstepwasrepeatedthreetimestoremoveundissolvedhexadecylammoniumbromideasmuchaspossible.Thetwokindsofgoldsolsinthebottomwerepipettedintoanewcentrifugetube.Deionizedwaterwasusedtorestorethesetwokindsofgoldsolsbackto2mL.Byconductingtheaboveprocedures,theconcentrationofthegoldsolsincreased.Then,0.1mLof10-5g/Lcrystalvioletsolutionwasaddedintothegoldsolssothatthesolutionsweredispersedultrasonically.Thesolutionsweremovedintoquartzcapillarieswhosetwosideswereobdurate.Thecapillarieswithsamplesweremaintainedfor30min.TheparametersofRamanspectroscopy(madebyRenishaw,UK)wereasfollows:excitationwavelengthis514.5nm,laserpoweris5mW,andintegrationtimeis10s.Fig.6(a)showsRamanspectraofthelow-concentrationcrystalvioletsolutionwithdifferentappearancesofgoldnanoparticles.Curve(a)istheRamanspectrumoflowconcentrationcrystalvioletsolution.Curve(b)isthespectraofthesolutionwithsphericalgoldnanoparticles.Curve(c)isthespectraofthesolutionwithshuttle-shapedgoldnanoparticles.Curve(d)isthespectraofthesolutionwithstar-shapedgoldnanoparticles.Fig.6(b)illustratestherelationshipbetweenpeakpositionandparticle’sdiameter,indicatingthatthegoldnanoparticleswithlargerdiametercanbetterenhanceRamansignal.GoldnanoparticlescanenhanceRamansignalofthesolutionwithverylowconcentration,whichisaffectedbydifferentpatternsofthenanoparticles.AlthoughmentalmoleculeshavenoRamanpeak,theycanenhanceRamanintensityofothermoleculesinverylowconcentration.TheRamanpeakcannotbefoundincurve(a),butisfoundclearlyincurves(b),(c)and(d).Curves(b),(c)and(d)haveRamanpeaksat785,901,1025,1163,1279,1358,1464,1517,1569,1607and1617cm-1,whichareallthewavenumbersofcrystalvioletRamanpeaks.Fig.6demonstratesthatallspherical,shuttleshapedandstar-shapedgoldnanoparticlescanenhanceRamanintensity.Whencrystalvioletmoleculesareabsorbedbygoldnanoparticles,theLSPRofgoldnanoparticlescanincreaseRamanintensityofthecrystalvioletmolecules.ItcanbeseenfromFig.6thatthestar-shaped