半導(dǎo)體量子點(diǎn)在癌癥成像與治療中的應(yīng)用課件

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Diagnosisand

Therapeutics

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DiagnosisandTherapeutics導(dǎo)帶空帶空帶價(jià)帶價(jià)帶}Eg}Eg導(dǎo)體非導(dǎo)體半導(dǎo)體絕緣體{CompanyLogoLogoLogoLogo

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DiagnosisandTherapeutics對(duì)于半導(dǎo)體而言，由于其費(fèi)米能級(jí)位于價(jià)帶和導(dǎo)帶這兩個(gè)帶之間，因此，帶邊控制著其低能光學(xué)和電子行為，由于帶邊的態(tài)密度很小，所以其少量的變化就會(huì)引起物體光學(xué)和電子行為的很大改變，而且體積越小，態(tài)密度也越小，變化就越大，所以與金屬不同，半導(dǎo)體的光電性質(zhì)在很大程度上依賴于材料的尺寸，對(duì)于即使含有上萬(wàn)個(gè)原子的晶體也是如此。CompanyLogoLogoLogoLogo

Logo半導(dǎo)體能帶工程1.半導(dǎo)體固溶體定義：兩種或兩種以上同一類型的半導(dǎo)體材料組成的合金?？煽闯墒莾煞N或兩種以上的材料通過(guò)互溶方式形成，每種材料的含量用組分表示。

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、固溶體的基本特征

性質(zhì)一般會(huì)隨組份比的變化而連續(xù)變化。能帶結(jié)構(gòu)，載流子遷移率、折射率，等。（1）晶格常數(shù)服從Vegard關(guān)系：某種晶體的晶格常數(shù)等于所組成化合物晶格常數(shù)乘于其所占的比例之和兩種化合物組成：

α(GaAsxP1-x)=xαGaAs+(1-x)αGaP

三種化合物組成:α(AlxInyGa1-x-yN

)=xαAlN+yαInN+(1-x-y)αGaN

通過(guò)對(duì)固溶體晶格常數(shù)的測(cè)定，可以確定固溶體的組分。CompanyLogoLogoLogoLogo

Logo（2）能帶結(jié)構(gòu)是其組分的函數(shù)：某些固溶體的禁帶寬度可表示為組分比的線性函數(shù)：

EgAB=xEgA+（1-x）EgBEgABC=xEgA+yEgB+（1-x-y）EgC某些固溶體的禁帶寬度隨組分變化偏離線性規(guī)律，可用模型表示：

Eg=a+bx+cx2GaxInyP：1.351+0.643x+0.786x2裁剪材料的能帶結(jié)構(gòu)，對(duì)特定固溶體禁帶寬度隨組分的變化關(guān)系研究。

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DiagnosisandTherapeutics1.尺寸影響下的藍(lán)移球形結(jié)構(gòu)的量子點(diǎn)半徑用R表示，α為玻爾半徑，激子的能量與量子點(diǎn)尺寸和結(jié)構(gòu)都有關(guān)系，當(dāng)R<<α?xí)r，激子受到強(qiáng)限制，量子點(diǎn)的尺寸作用效果大于庫(kù)倫作用，激子的能量可以近似的看成是電子與空穴的能量和；而當(dāng)R>>α的時(shí)候，激子受到弱限制，這個(gè)時(shí)候考慮量子點(diǎn)尺寸的同時(shí)也要考慮庫(kù)倫作用。CompanyLogoLogoLogoLogo

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DiagnosisandTherapeutics求得量子點(diǎn)材料的禁帶寬度：由此可見，隨著量子點(diǎn)材料的尺寸減小，禁帶寬度增大，吸收光譜產(chǎn)生藍(lán)移現(xiàn)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