半导体量子点在癌症成像与治疗中的应用课件

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Diagnosisand

Therapeutics

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DiagnosisandTherapeutics导带空带空带价带价带}Eg}Eg导体非导体半导体绝缘体{CompanyLogoLogoLogoLogo

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DiagnosisandTherapeutics对于半导体而言，由于其费米能级位于价带和导带这两个带之间，因此，带边控制着其低能光学和电子行为，由于带边的态密度很小，所以其少量的变化就会引起物体光学和电子行为的很大改变，而且体积越小，态密度也越小，变化就越大，所以与金属不同，半导体的光电性质在很大程度上依赖于材料的尺寸，对于即使含有上万个原子的晶体也是如此。CompanyLogoLogoLogoLogo

Logo半导体能带工程1.半导体固溶体定义：两种或两种以上同一类型的半导体材料组成的合金。可看成是两种或两种以上的材料通过互溶方式形成，每种材料的含量用组分表示。

SixGe1-x;Si0.4Ge0.6：Si：0.4，Ge：0.6GaAsxP1-x;GaAs0.3P0.7：GaAs：0.3，GaP：0.7InxGa1-xN;In0.2Ga0.8N：InN：0.2，GaN：0.8AlxInyGa1-x-yN

;Al0.1In0.3Ga0.6N

：AlN：0.1，InN：0.3，GaN：0.6CompanyLogoLogoLogoLogo

Logo2、固溶体的基本特征

性质一般会随组份比的变化而连续变化。能带结构，载流子迁移率、折射率，等。（1）晶格常数服从Vegard关系：某种晶体的晶格常数等于所组成化合物晶格常数乘于其所占的比例之和两种化合物组成：

α(GaAsxP1-x)=xαGaAs+(1-x)αGaP

三种化合物组成:α(AlxInyGa1-x-yN

)=xαAlN+yαInN+(1-x-y)αGaN

通过对固溶体晶格常数的测定，可以确定固溶体的组分。CompanyLogoLogoLogoLogo

Logo（2）能带结构是其组分的函数：某些固溶体的禁带宽度可表示为组分比的线性函数：

EgAB=xEgA+（1-x）EgBEgABC=xEgA+yEgB+（1-x-y）EgC某些固溶体的禁带宽度随组分变化偏离线性规律，可用模型表示：

Eg=a+bx+cx2GaxInyP：1.351+0.643x+0.786x2裁剪材料的能带结构，对特定固溶体禁带宽度随组分的变化关系研究。

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DiagnosisandTherapeutics1.尺寸影响下的蓝移球形结构的量子点半径用R表示，α为玻尔半径，激子的能量与量子点尺寸和结构都有关系，当R<<α时，激子受到强限制，量子点的尺寸作用效果大于库伦作用，激子的能量可以近似的看成是电子与空穴的能量和；而当R>>α的时候，激子受到弱限制，这个时候考虑量子点尺寸的同时也要考虑库伦作用。CompanyLogoLogoLogoLogo

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DiagnosisandTherapeutics求得量子点材料的禁带宽度：由此可见，随着量子点材料的尺寸减小，禁带宽度增大，吸收光谱产生蓝移现象。CompanyLogoLogoLogoLogo

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LogoNanomaterial-basedstrategiesfortumordiagnosis,imaging,andtherapy.CompanyLogoLogoLogoLogo

LogoNanomaterial-basedstrategiesfortumordiagnosis,imaging,andtherapy.CompanyLogoLogoLogoLogo

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DiagnosisandTherapeuticsThecriticalissuesincancerdiagnosisandtreatmentareaddressedbasedonnovelnanotechnologiessuchasreal-timein-vivoimaging,drugstorageandrelease,andspecificcancer-celltargeting.CompanyLogoLogoLogoLogo

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DiagnosisandTherapeuticsHowever,themajorlimitingfactorinharnessingthemaximumpotentialofQDsasmultifunctionalimagingprobesanddeliverysystemsistheirinherentcytotoxicity;mostofthewell-establishedQDsarecomposedofhighlytoxicelements,suchascadmium(Cd),selenium(Se)ortellurium(Te).

Thereisanurgentneedtodevelopasimpleandstraightforwardmethodologythataffordsboththesynthesisofnon-toxicQDsandtheversatilityofgeneratingalibraryofQDswithtunablepropertiesfavoringtheiruseasimagingagentsinbiology.SotheresearchersdevelopedZnS-AgInS2QDsasnon-toxicmolecularprobes.CompanyLogoLogoLogoLogo

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DiagnosisandTherapeuticsFigure2.PhotoluminescentpropertiesoftheZAISQDlibrary.A)RepresentativefluorescentimageoftheentirelibraryofZAISQDswithvaryingcompositions(ZnxS-AgyIn1-yS2)synthesizedviathesonochemicalapproach.B)HeatmapdepictingthePLintensity(zaxis)vs.ZnandAg/Inconcentrations(xandyaxis)forselectcompositionsoftheZAISnanoparticlelibrary.Columncolorindicatesthemaximumemissionwavelength.λe=365nmλCompanyLogoLogoLogoLogo

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DiagnosisandTherapeuticsFigure3.Physicalcharacterizationofthe

ZnxS-AgyIn1-yS2QDs.A)X-rayFluorescenceanalysisofoneoftheZAISQD(x=0,y=0.2)showingtheelementalcompositionandrelativeatomicmoleratiosoftheconstituentelements.Thecompositionagreestothatcalculatedtheoreti-cally.B)X-raydiffractionpatternsoftheZAISQDspreparedusingsonochemistry.Thevaluesofxandyareindicatedinthefigure.ReferencepatternsofbulkZnSandAgInS2arealsoshown.BroadpeakwidthisattributedtotheamorphousnatureoftheZAISQDs.(C)TEMimagesofoneoftheZAISQDs(x=0,y=0.2)clearlyshowsthemonodispersityandnarrowsizedistribution.Insetshowsthehighresolutionimageofasinglenanoparticle(Scalebar=10nm).(D)Photoluminescencespectraofselectwater-solubleZAISQDs(a:x=0.6,y=0.5.;b:x=0.3,y=0.4;c:x=0,y=0.2;d:x=0,y=0.5)CompanyLogoLogoLogoLogo

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DiagnosisandTherapeuticsThephysicochemicalandbio-relevantpropertiesoftheresulting