简介:利用水热法成功地实现了掺杂(Ag、Fe、Al、Ce、Ni、Pb)纳米氧化锌(ZnO)粉体的制备,通过X射线衍射(XRD)、扫描电镜(SEM)等表征方法,系统地分析了掺杂元素种类、掺杂浓度对纳米ZnO的结构、形貌的影响,以及不同测试温度下各种相应纳米ZnO电阻率的变化,X射线衍射谱表明,掺Ag、Fe、Ce、Ni纳米ZnO的结晶度降低;掺Al和Pb纳米ZnO的结晶度变化不大.SEM形貌表征显示,未掺杂的纳米ZnO为片状;掺Ag、Al的纳米ZnO为颗粒状;掺Fe、Ni、Pb的纳米ZnO为六方短柱状.电阻率测试表明,相比未掺杂纳米ZnO,掺Ag、Ce的纳米ZnO电阻率增大,且在一定温度范围内随温度的增加具有较大幅度的变化;掺Fe的纳米ZnO电阻率相对降低.掺杂浓度由1%增加到3%时,掺Ni的纳米ZnO电阻率增大;掺Fe、Al和Pb的纳米ZnO电阻率减小.
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简介:采用溶胶-凝胶(Sol-gel)法和旋涂法在单晶硅片表面制备了5%(摩尔分数)Er3+掺杂的Yb2Ti2O7薄膜.采用X射线衍射仪(XRD)和扫描电子显微镜(SEM)对薄膜的相结构和表面及截面形貌进行了表征,通过荧光光谱仪检测了薄膜的上转换发光特性.结果表明:Ep+掺杂的Yb2Ti2O7薄膜为单一面心立方Yb2Ti2O7相结构,薄膜表面较光滑平整,颗粒尺寸约为80nm.976nm半导体激光器(LD)激发Er3+掺杂的Yb2Ti2O7薄膜获得了较强的绿色、红色和红外上转换发光,分别对应于Er3+的2H11/2/4S3/2→4I15/2、4F9/2→4I15/2和4S3/2→4I13/2跃迁.Er3+掺杂Yb2Ti2O7薄膜的绿色和红色上转换发光均为双光子吸收过程.Er3+掺杂Yb2Ti2O7薄膜和粉末的上转换发光光谱还出现了绿色和红色上转换发光强度的变化.
简介:ToxicityofMgOandZnOnanoparticlesatconcentrationsof250,500or1000mg/LforCitrusmaximaseedlingswasinvestigatedtoevaluatethepotentialityoftheiruseasnano-fertilizers.UptakeandtranslocationofmetaloxidenanoparticlesandlipidperoxidationweremeasuredandcomparedwiththoseofplantsexposedtothehighestequivalentconcentrationsofMg2+andZn2+.MgOnanoparticlesweretranslocatedfromrootstoshoots,whiletranslocationofZnOnanoparticleswaslow.ExposuretoMg2+andMgOatallconcentrationsentailedseveretoxicityandstrongoxidativestress.ZnOnanoparticlesshowedonlymildtoxicity,whileZn2+causedleafveinchlorosisandstrongoxidativestresstoplantshoots.Inconclusion,thetoxicityofMgOnanoparticlestotheplantresultedfromthedissolvedMg2+concentration,whilethatofZnOnanoparticleswasnotcorrelatedwiththedissolvedZn2+concentration.OurfindingsaresignificantfordevelopmentandapplicationofMgOandZnOnanoparticlesasnano-fertilizersinagriculture.
简介:AsimpleapproachtosynthesizeZnOmicrostructureswasreportedusingdodecylamine,hexadecylamineandoleylamineastemplateagents.ThesynthesizedZnOwascharacterizedbyXRD,FESEM,TEM,EDSmapping,FTIR,UV-visDRS,RamanspectroscopyandBETanalysis.HierarchicalorientedZnOmicrostructureswereobtained.ThephotocatalyticperformanceofZnOpreparedwithdifferenttypesofalkylamineswasevaluatedbythedegradationofmethyleneblue(MB)andmethylorange(MO).Theresultssuggestedthatalkylaminecontrolthenucleation,growthandmorphologyofZnO.ThephotocatalyticpropertiesofZnOonthedegradationofMBandMOdecreasedwithincreasingthealkylchainlengthinalkylamine.
简介:Here,wereportthesynthesisandcharacterizationsofsol—gelderivedzincoxide(ZnO)quantumdots(QDs)usingzincacetatedihydrate(Zn(CH3COO)2·2H20)andlithiumhydroxidemonohydrate(LiOH·H20)asrawmaterial.Theas-preparedZnOQDswasannealedatdifferenttemperature(400,700,and900℃)andthestructural,opticalpropertieswereinvestigatedbyX-raydiffraction(XRD),highresolutiontransmissionelectronmicroscopy(HRTEM),UV—Visandphotoluminescence(PL)spectroscopy.ThepowderXRDpatternsoftheobtainedsamplesshowedtheformationofsingle-phasewurtzitestructureandthemorphologicalchangeshavebeenobservedwithincreasingannealingtemperature.Intheabsorptionspectra,theopticalbandgapofnanocrystallineZnOQDsdecreasedfrom3.18to3.11eVandtheparticlesizeincreasedwithincreasingtemperature.InthePLspectra,abroadgreenemissionpeakrelatedtodefectlevelsinthevisiblerangeofthespectrahavebeenrecorded.