核殼結(jié)構(gòu)CdS量子點的熒光性質(zhì)研究的中期報告

核殼結(jié)構(gòu)CdS量子點的熒光性質(zhì)研究的中期報告摘要：本報告介紹了核殼結(jié)構(gòu)CdS量子點的制備方法和熒光性質(zhì)研究的進展。首先，通過溶劑熱法合成了CdS核殼結(jié)構(gòu)量子點，并使用透射電子顯微鏡（TEM）、X射線衍射（XRD）和紫外-可見吸收光譜（UV-Vis）對其進行了表征。然后探究了CdS的核殼結(jié)構(gòu)對量子點熒光性質(zhì)的影響，發(fā)現(xiàn)CdS量子點的激發(fā)波長和熒光強度可以通過調(diào)節(jié)其核殼結(jié)構(gòu)的厚度得到調(diào)控。進一步探究了CdS量子點的熒光特性對其熒光傳感應用的適用性，結(jié)果表明CdS量子點可以用于檢測水中離子摻雜情況的鑒定，為其在環(huán)境和生物醫(yī)學領域的應用提供了新的可能性。關鍵詞：CdS量子點；核殼結(jié)構(gòu)；熒光性質(zhì)；熒光傳感Introduction量子點由于其優(yōu)異的熒光性質(zhì)，例如可調(diào)控的激發(fā)和熒光波長、高熒光量子產(chǎn)率和穩(wěn)定的光學性質(zhì)等，在生物醫(yī)學成像、綠色能源、化學傳感等領域應用前景廣闊。其中，CdS量子點具有較大的帶隙和較高的激子束縛能，因此其熒光性質(zhì)在過去的研究中得到了廣泛的關注。然而，由于CdS量子點本身的光化學穩(wěn)定性差，易被氧化和光降解等問題限制了其在實際應用中的發(fā)展。為了解決這一問題，研究者采用了包覆、修飾、摻雜等手段對CdS量子點進行了改性，其中核殼結(jié)構(gòu)作為一種有效的改性手段受到了廣泛關注。Inthisstudy,wefocusedonthepreparationandfluorescencepropertiesofcore-shellCdSquantumdots.Firstly,CdScore-shellquantumdotsweresynthesizedbyasolvothermalmethodandcharacterizedbytransmissionelectronmicroscopy(TEM),X-raydiffraction(XRD),andultraviolet-visibleabsorptionspectroscopy(UV-Vis).Then,theinfluenceofthecore-shellstructureofCdSquantumdotsontheirfluorescencepropertieswasexplored.ItwasfoundthattheexcitationwavelengthandfluorescenceintensityofCdSquantumdotscanbecontrolledbyadjustingthethicknessoftheircore-shellstructure.Furthermore,thesuitabilityofCdSquantumdotsforfluorescencesensingapplicationswasinvestigated.TheresultsshowedthatCdSquantumdotscanbeusedfortheidentificationofiondopinginwater,providinganewpossibilityfortheirapplicationsinthefieldsofenvironmentalprotectionandbiomedicalimaging.MaterialsandmethodsCdScore-shellquantumdotsweresynthesizedbyasolvothermalmethodusingthioureaasasulfursource.Briefly,CdOnanoparticleswerefirstdispersedinethyleneglycolthroughultrasonication,andthenthioureawasaddedtothesolution.Thereactionwasmaintainedat160°Cundernitrogenatmospherefor3hours.TheresultingCdSnanoparticleswerecoatedwithalayerofZnSbyaddingzincacetateand2-mercaptoethanoltothesolutionunderthesameconditions.TheobtainedsampleswerecharacterizedbyTEM,XRD,andUV-Vis.ThefluorescencespectraofCdSquantumdotsweremeasuredusingaspectrofluorometer.ResultsanddiscussionTEMimages(Figure1A)showedthattheCdScore-shellquantumdotshadauniformsizedistributionandasphericalshape,withanaverageparticlesizeofaround4.5nm.TheXRDpatterns(Figure1B)confirmedtheformationofcubicCdSandZnSphasesinthecore-shellstructure.TheUV-Visabsorptionspectra(Figure2A)showedthattheCdScore-shellquantumdotshadanabsorptionedgeataround440nm,indicatingtheirstrongblue-lightabsorptionability.ThefluorescencepropertiesofCdSquantumdotswereinvestigatedundertheexcitationwavelengthrangeof340-400nm.AsshowninFigure2B,thefluorescenceintensityandpeakpositionofCdSquantumdotswerefoundtobedependentontheircore-shellstructure.Specifically,theCdS/ZnScore-shellquantumdotsexhibitedahigherfluorescenceintensityandared-shiftedpeakthantheCdScorequantumdots.TheresultsindicatedthattheadditionoftheZnSshellcouldeffectivelyimprovetheemissionpropertiesofCdSquantumdots.Moreover,theCdS/ZnScore-shellquantumdotswereexploredfortheirfluorescencesensingapplications.Byaddingdifferentions(includingNa+,K+,Mg2+,Ca2+,andBa2+)totheCdS/ZnSquantumdotsolution,thefluorescencequenchingeffectofdifferentionsonthequantumdotswasinvestigated.ItwasfoundthatthefluorescenceintensityofCdS/ZnSquantumdotswasquenchedtovaryingdegreesbydifferentions,especiallyBa2+.TheresultsdemonstratedthatCdS/ZnSquantumdotscanbeusedfortheidentificationofiondopinginwater.ConclusionInthisstudy,wehavesuccessfullypreparedCdScore-shellquantumdotsandinvestigatedtheirfluorescenceproperties.Theresultsshowedthatthecore-shellstructureofCdSquantumdotscouldsignificantlyinfluencetheiremissionpropertiesandthattheadditionofZnScouldeffectivelyimprovetheirfluorescenceintensityandpeakposition.Furthe