简介:AnovelphotoelectrochemicalbiosensorincorporatingnanosizedCdSsemiconductorcrystalswithenzymetoenhancephotochemicalreactionhasbeeninvestigated.CdSnanoparticlesweresynthe-sizedbyusingdendrimerPAMAMasinnertemplates.TheCdSnanoparticlesandglucoseoxidase(GOD)wereimmobilizedonPtelectrodevialayer-by-layer(LbL)techniquetofabricateabiological-inorganichybridsystem.Underultravioletlight,thephoto-effectoftheCdSnanoparticlesshowedenhancementofthebiosensortodetectglucose.PtnanoparticlesweremixedintotheNafionfilmtoimmobilizetheCdS/enzymecompositesandtoimprovethechargetransferofthehybrid.Experimentalresultsdemon-stratethedesirablecharacteristicsofthisbiosensingsystem,e.g.asensitivityof1.83A/(mMcm2),lowerdetectionlimit(1M),andacceptablereproducibilityandstability.
简介:CdSthinfilmsweredepositedbytheionlayergasreaction(ILGAR)method.Structural,chemical,topographicaldevelopmentaswellasopticalandelectricalpropertiesofas-depositedandannealedthinfilmswereinvestigatedbyXRD,SEM,XPS,AFMandUV-VIS.Theresultsshowedthatthethinfilmsareuniform,compactandgoodinadhesiontothesubstrates,andthegrowthofthefilmsis2.8nm/cycle.Theevolutionofstructureundergoesfromthecubicstructuretothehexagonalonewithapreferredorientationalongthe(002)planeafterannealingat673K.AnamountofC,OandClimpuririescanbereducedbyincreasingthedryingtemperatureorbyannealinginN2atmosphere.ItwasfoundthatthebandgapoftheCdSfilmsshiftstohigherwavelengthafterannealingorincreasingfilmthickness.Theelectricalresistivitydecreaseswithincreasingannealingtemperatureandfilmthickness.
简介:CdSnanocrystalsofvariousshapesweresynthesizedbyusingcadmiumethyldithiocarbonatio(xanthate)asasingleprecursorundersolvothermalcondition.Thereactiontemperature,cadmiumconcentration,andsolventsdeterminetheCdSmorphology.MultipodalCdSstructuresofdifferentfractionsofallparticleswereobtainedattemperaturesrangingfrom100to180℃withthecorrespondingprecursorconcentrationsinethylenediamine(EDA)solution.Thisapproachisdifferentfromthatreportedintheliterature,whereEDAisregardedasasolventfavorabletotheformationofCdSnanorodsinsteadofpods.UniformCdSmultipodswerepreparedat160℃with1.0gofcadmiumxanthate.TheformationofCdSmultipodsinEDAsolutionmaybeattributedtoasynergisticeffectbetweenthereactiontemperatureandCdconcentration,i.e.,thermodynamicailyandkineticallycontrolledgrowthoftheCdSwurtzite(WZ)andzincblende(ZB)phases,asconfirmedbythestructuralcharacterizationofthecomponentCdScrystals.EDAandxanthateligandsactasco-assistedcappingagentsinthegrowthofCdSmultipods.WhenusingN,N-dimethylformamide(DMF)andethyleneglycol(EG)assolvents,theCdSappearsastriangularparticlesandflower-likemicrospheresassembledbypolyhedrons,respectively.