水热法制备纳米ZnSWord下载.docx
- 文档编号:17929926
- 上传时间:2022-12-12
- 格式:DOCX
- 页数:6
- 大小:21.92KB
水热法制备纳米ZnSWord下载.docx
《水热法制备纳米ZnSWord下载.docx》由会员分享,可在线阅读,更多相关《水热法制备纳米ZnSWord下载.docx(6页珍藏版)》请在冰豆网上搜索。
以十六烷基三甲基溴化铵(CTAB)为表面活性剂,利用水热法通过二吡啶硫氰酸锌分解制备了ZnS纳米线,并用SEM、XRD.EDX和HR-TEM等方法对其纳米结构进行了表征。
实验结果表明,反应时间和表面活性剂浓度是决定纳米ZnS最终形貌的关键凶素.CTAB起到了纳米线生长的分子一诱导模板作用。
Nanostructurehasarosetreruendousinterestaruongtheresearchersworkinginallfieldsincludingphysicstobioscience.Frombasicsciencetotechnologistsfortheirimprovedphysicalandchemicalpropertiesandapplicationssuperiortotheirbulkcounterparts.Sincethefirstdiscoveryofcarbonnanotubes.one-dimensional(ID)semiconductormaterialssuchasnanorods.nanowires.nanotubesandnanobelts/nanoribbonshaveattractedextensiveinterestbecauseoftheirfundamentalphysical.chemical,optical,electricalandmagneticproperties,andtheirpotentialapplicationsinnano-scaledevices.ItiswellknownthatIDnanostructurecanplayanimportantrolebothasinterconnectandfunctionalunitsinfabricatingelectronic,optoelectronic.electrocheruicalandelectroruechanicaldeviceswithnanoscaledimension.1Dnanostructurehavebeensynthesizedthroughavarietyofsynthesistechniquesuchastemplate-directedsynthesisc5l,Vaporsolidgrowth,vapor-liquid-solid(VLS)growthm.solu-tion-liquid-solid(SLS)growthcs]etc.Avarietyofmetalc9Lsemiconductingoxidesuo]indifferentIDnanoformshavebeenreportedsofar.
Outofthesematerials.zincsulfide.aII-VIsemiconductor.isoneof'
themoststudiedmaterialsforitswiderangeoftechnologicallyimportantproperties.ZincSulfide(ZnS)hasawidebandgapof3.72eVforcubicphasec"
and3.77eVfortheatrooruteruperature.Itisalight-eruittingdiodes,injectionlasers.cathoderaytubes,flatpaneldisplaysandIRwindows.ZnSisalsoimportantforphotoluminescence.electroluminescence.etc.Recently,opticalwaveconfiningandlasinghasbeendemonstratedinZnSnanoribbonsU3lInrecentyears,nanocrystallineZnShasattractedmuchattentionbecausepropertiesinnanoformsdiffersignificantlyfromthoseoftheirbulkcounterparts.Therefore.Muchefforthasbeendevotedtocontrolthesize.morphologyandcrystallinityoftheZnSnanocrystalswithaviewtotunetheirphysicalproperties.
Inthisstudy,wepresentarelativelysimpleandeffectiveprocedureforsynthesisofl-DZnSviahydrothermalreactionat2000Cusingadipyridylzincthiocyanatecolloidalsolution,cetyltrimethylammoniumbromide(CTAB)asasurfactant.Theinfluenceofsurfactantandreactiontimeonthemorphologyhasbeeninvestigated.
1Experiment
HydrothermalreactionofZnSnanowirewithsurfactantCTAB
AllreagentswereanalyticalgradeCTAB(0,0.12,0.240r1.44mmoI-L~1)and3mLofmethoxyethanolsolutionofdipyridylzincthiocyanate(0.24mmolL-'
)wereputintoTeflonlinedautoclaveof50mLcapacity,andthenwasfilledwithdoubledistilledwaterupto80%ofthetotalvolume.Afterbeingsealed,theautoclavewasheatedt0200OCandmaintainedfor2h.andthencooledtoroomtemperature.Theresultingblacksolidfractionwaswashedwithdeionizedwaterandthenwithabsoluteethanol.Finallytheproductsweredriedundervacuumat400C.
有表面活性剂的硫化锌纳米线的水热反应
实验时把所有的试剂析,不同等级的CTAB和3毫升联吡啶硫氰酸甲氧基乙醇溶液放入盛有50毫升的聚四氟乙烯容器内,然后加入蒸馏水直至占总体积的百分之八十。
之后加热到二XX保持两个小时,接着冷却至室温。
把生成的黑色固体用等离子水冲洗接着再用纯酒精清洗一次,最后把产品放到四十度真空中干燥。
。
1.2Characterization
Highresolutiontransmissionelectronmicroscopy(HRTEM)observationsweredoneonHitachimodesH700A-2apparatusequippedwithanEDAXEDSdetectorwithanacceleratedvoltageof200kV.Highresolutionscanningelectronmicroscopy(HR-SEM)imageswereobtainedbyOPTONCSM-950withanacceleratedvoltageof160kV.UV-VspectrawererecordedonaUnicoUV-2201UV-Visspectrometerwithrueasuredwavelengthrangefrom900nmto200nmandslitof1muandscanspeedof300nm.min-l.X-raydiffraction(XRD)patternswereobtainedonaRigakuD/Max2550XwithCuKceradiation(40kV.200ruA.A=0.154186nm)and20rangeof200-800andscanspeedof0.020.s-'
.PLstudywasperformedonHitachiF-2500withslitof1nmandscanspeedof300nm.min-l.
在装有一个200千伏的加速电压的设备的高分辨率的日立H700A-2上进行电子显微检测.,高分辨率扫描显微图像通过OPTONCSM-950用160伏特的加速电压来获得.通过UnicoUV-2201UV-V分光仪波长在九百纳米到二百纳米、缝宽为1微米、扫描速率为300纳米每分钟得到紫外光谱。
X衍射图像铜电子辐射在D/Max2550X衍射机,扫描速率为0.020.s-'
.缝宽1nm。
扫描速率为每分钟300纳米在HitachiF-2500上进行试验
2Resultsanddiscussion
2.1EffectoftheconcentrationofCTABonthemorphologyofnano-ZnS
Figs.la-dshowSEMimagesoftheZnSnanostructuresynthesizedwithvariedamountsofCTABsurfactant.TheseiruagesclearlyrevealthatthemorphologyofZnSnanostructurevariessignificantlywiththeamountofCTAB.TheshapeofZnSnanostructurevariesfrorusphericalattheratioofZn:
CTAB=I:
O(Fig.la)tohigh-yieldwireslikeattheratioofZn:
CTAB=1:
6(Fig.ld)
withthereactiontimeof2h.ThesimilarphenomenawereobservedfromUV-VisspectraofZnSnanostructure(Fig.2).CurveainFig.2showstheabsorptionofZnSnanostructurepre-paredwithoutCTABandthereisapeakatabout337nrucorrespondingtoabandgapof3.68eV.abulkcubicZnSreportedinreference[14lWiththeincreaseofCTAB.theabsorptionpeakshiftsshorter(blue)to330nm(Curveb),325nm(Curvec)and289nm(Curved),respectively,whichcorrespondstoabandgapofhexagonalZnS.ThebandgapofbulkhexagonalZnSis3.80eV['
4].SOitsuggeststhatthepresenceofCTAB
2.2Effectofreactiontimeonthemorphologyofnano-ZnS
InadditiontotheeffectofCTABconcentration.reactiontimeisanotherimportantfactorthatinfluencestheshapeandsizeofZnSnanostructure.Acomparisonbetwe.entheimagesofZnSnanostuctures,preparedwiththesameCTABconcentrationandwithvarious(0.5and2h)reactiontimes.showsthetime-relatedshapeevolutionprocessofZnSnanostructure.Asmentionedabove.thenanowiresobtainedwithl.44mmol.L-IofCTABwithareactiontirueupt00.5hconsistonlyofafewin-dividualwire-likestructureswithawidthof40nmandalengthof150nruaswellasthesphericallyshapedZnS(60nmindiameter)(Fig.3a).After2hofsynthesis.theyieldofwire-shapedZnSincreases:
wire-likestructureswithawidthof60nmandale.ngthof2000nmareseen(Fig.3b).Inallthecasesde.scribed(reactionwithsurfactant),attheshorterreactiontimedurationrespectively(0.5h)weseeonlythebeginningoftheevolutionofZnSfromcubicshapedwire-likemorphologicalasserublies.whileafter2hofsynthesis,theZnSnanowiresyieldincreaseswithincreasingsizesofZnScrystal.Fromthetime-relatedshape-evolutionprocess,itseemsthatincrasingthere.actiondurationt02h,usingvariousCTABconcentrationsleadstoahighyieldofwire-likestructures.
2.3FurthercharacterizationofZnSnanostructure
Fig.4a,bandcaretheXRDpatternsofthesynthesizedZnSnanostucturepreparedwithoutCTABandinpresenceof0.24mruol-L-'
.1.44rumol.L-10fCTABwiththereactiontimeof2h.respectively.AlltheofZnSnanostucturepreparedwithoutCTAB(a)andinpresenceof'
0.24mmolL-I(b),(c)of'
CTABwiththereactiontimeof'
2h,respectivelvdiffractionpeaksinFig4acanbeindexedtocubicZnS(PDFCardNo.5-566)andinFig.4b,ccanbeindexedtohexagonalphaseZnS(PDFCardNo.12-688),whichisingoodagreementwiththeresultsobtainedfromUVVisspectra(Fig.2).NoimpuritiessuchasZn.NioorintermediaryphasezincsulfidesaredetectedintheXRDpatternsofFig.4bandc.ButthecharacteristicdiffractionpeaksinFig.4bislessobviousthanthoseinFig.4c,whichindicatesthattheconcentrationofCTAB
dlfectsthecrystalintegrality.
TypicalEDXpattemofas-obtainedZnSsampleisshowninFig.5.TheresultsshowthattheZnSnanowiresarecoruposedofZnandSandtheratioofZntoSis1.08:
l,inagreementwiththeexpectedvalue.EnergylkeVInFig.6,HR-TEMimageofZnSshowsthattheyarecomposedofabout7nmZnSnanocrvstalsasseruFig.6TEMimageof'
ZnSnanowireandHR-TEMimageoftheZnSnanowire(inset)preparedusing1.44mmolL-lof'
2hbliesbecauseneck-likeconnectionsaruongtheadjacentnanocrystalsareclearlyobserved.Thelatticeplanesof'
ZnSnanocrystalsareclearlyvisibleintheinsetofFig.6.Fig.7illustratesthephotoluminescence(PL)spectrumofZnSnanowireswithanexcitationwavelengthof335nm.Theappearanceofanarroweruissionpeakatabout452muisweak.Abroadbandatabout520nmisalsoobserved.whichcanbedividedintotwopeaksat523muand533nm,repectively,deruonstratingthatthesenonawiresruayhavepotentialapplicationsinop-
toelectronicdevices.
Thenucleationandgrowthconditionsofnano-ZnSwereexaruinedwithoutandwithvariousconcentrationsofcationicsurfactantCTAB.ThisgrowthprocesscouldberelatedtotheinteractionoforientedsurfactantchainsandformattedZnSnanowires.Uniformandorderedchainstructure(16carbonatoms)iseasilyadsorbedonthesurfaceofZnScolloidalparticles.
WhenthesurfaceofthecolloidalZnSadsorbsCTAB.theactivitiesofcolloidgreatlydecreaseandthegrowthrateofthecolloidinsomecertaindirectionwillbeconfined.TheadditionofmoreCTABinthecolloidalsolutionruodifiesthegrowthkineticsofthegrowingcolloids.whichfinallyleadstoanisotropicgrowthofnanocrystals.Investigationshavebeendonewithdifferentconcentratio
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 法制 纳米 ZnS