该【thermal dependence of optical parameters of thin polythiophene films blended with pcbm janusz jaglarz论文 】是由【小舍儿】上传分享，文档一共【13】页，该文档可以免费在线阅读，需要了解更多关于【thermal dependence of optical parameters of thin polythiophene films blended with pcbm janusz jaglarz论文 】的内容，可以使用淘豆网的站内搜索功能，选择自己适合的文档，以下文字是截取该文章内的部分文字，如需要获得完整电子版，请下载此文档到您的设备，方便您编辑和打印。:..polymersArticleThermalDependenceofOpticalParametersofThinPolythiopheneFilmsBlendedwithPCBMJanuszJaglarz1,AnnaMa?ek2,*ra31MaterialsEngineering,MechanicalDepartment,CracowUniversityofTechnology,JanaPaw?aII37str.,31-867Cracow,Poland;******@.pl2DepartmentofElectronics,AGHUniversityofScienceandTechnology,Mickiewicza30Av.,30-059Cracow,Poland3InstituteofPhysics,CracowUniversityofTechnology,Warszawska24str.,30-841Cracow,Poland;******@cyf-*Correspondence:******@;Tel.:+48-692-942-715Received:22February2018;Accepted:17April2018;Published:19April2018Abstract:Themainpurposeofthisworkistoshowthethermaldependenceoftherefractiveandextinctionindicesofconjugatedpolymer?,wepresenttheresultsofopticalinvestigationsperformedforthefollowingpolymers:poly(3-hexylthiophene)(P3HT),poly(3-octylthiophene)(P3OT),andtheirblendswith[6,6]-phenylC61butyricacidmethylester(PCBM).Forouranalysis,wechosewell-knownpolythiophenessuchP3HTandP3OT,?–1700nmbyusingspectroscopicellipsometry(SE).Furthermore,weshowthetemperaturedependenceoftherefractiveindicesofpolythiophene?lmsforaheatingandacoolingprocessinthetemperaturerange25–130,thermo-oef?cientsandanopticalgapwereestablishedandarepresentedinthepaper,?ectionfromthestudied?-:conjugatedthin?lms;polythiopheneblends;spectroscopicellipsometry;thermo-,conjugatedpolymershaveattractedtheattentionofresearchersinthe?(OLEDs)[1–4]andphotovoltaic(PV)cells[2,4–6].Theuniqueoptoelectronicpropertiesofconjugatedpolymersaretheresultofbondsintheelectronicstructureofthepolymer[7].Becausebondsarenotstrong,itispossibletoicspectrum(VIS).parison,inmostsemiconductivepolymers,bondsaremuchstrongerthanbonds,andtheycanthereforebeexcitedonlybyphotonsfromtheultravioletrange(UV).Consequently,opticalpropertiesintheVISregiondeterminedbyelectronsandexcitationsareusuallynottakenintoconsideration[7].Theotherattractivepropertiesofconjugatedpolymersarethefollowing:theireasysolubility,environmentalstability,andsolutionprocessability[1,4].Polymers2018,10,454;doi::..Polymers2018,10,4542of13TheeffectivenessofsemiconductivepolymersusedasLEDorPVdevicesdependsontheiropticalparameters,especiallyontherefractiveindex(n),theextinctioncoef?cient(k),andtheopticalgap(Eg)[8–10].Theoptoelectronicpropertiesofconjugatedpolymersareafunctionoftheirchemicalstructure,hains,andthe?lmmorphology[1,11–13].Inturn,boththepolymermicrostructureandthe?,hemicalstructure,optoelectronicpropertiesvarywithchangingmolecularweight[5,14],thedepositionmethodused[15],solutionconcentration,and?lmthickness[15].Forourstudieswechosepoly(3-octylthiophene)(P3OT)andpoly(3-hexylthiophene)(P3HT)[16,17]andtheirblendswithfullerenederivatives([6,6]-phenylC61butyricacidmethylester,PCBM).P3HT:PCBMblendshavehighquantumef?ciencyandtheyareaverypopularresearchsubjectduetotheirphotovoltaicapplications[18–20].Therefore,theauthorsfocusedtheirattentiononanicdevicesarethebest(OLED,PVcells,polymertransistors,aniclasers)basedontheoptoelectronicpropertiesof,,itisimportanttochoosethebesturateinformationabouttheenergygapandtheelectronicstructureofpolymer?,thevalueoftheenergygapoftestedmaterialshasbeendeducedbasedonthedispersionoftheextinctioncoef?cientdeterminedbyspectrophotometricmeasurementsusingTaucorCodymodels[9,21].Themostsensitiveopticalmethodallowingthedeterminationoftheopticalparametersofthe?lmsandtheirthicknessisspectroscopicellipsometry(SE).TheSEallowsthedeterminationofthemostimportantquantitiesoftheelectronicstructureofpolymersemiconductors,carriedoutinthewidestpossiblespectralrange[8,12,22].Forlayerswiththicknesslessthan200nm,ellipsometrictechniquesgivethemostreliableresults[22].Theanalysisofellipsometricdataallowsestablishmentofthedispersionofopticalconstantsintherangeofclassicaloptics(190–2500nm).Inturn,thesedependenciesallowbandstructureparameterstobefoundusingappropriateopticalmodels[11,22,23].Theinteractionsbetweenapolymerthin?,theextinctioncoef?cient(k)andtherefractiveindex(n),-opticeffect[24,25].Insomepolymerlayerapplications(.,thermo-opticalswitches),largechangesinrefractiveindicesupontemperaturechangesarethebasisforthesedevices[24,26].Thus,thechangesinopticalconstantswiththetemperatureshouldbeconsideredinissuesrelatedtothedesignofdevicesbasedonpolymerconducting?,theopticalqualitiesofpolythiophenesandP3HT/PCBMaswellasP3OT/PCBMstructureshavemostlybeenstudiedatroomtemperature[10,21].,however,wepresenttheresultsofthermo-opticalanalysisdoneforP3HT/PCBMandP3OT/PCBMblendsinthetemperaturerangeof25–130-oef?cient(TOC)?aparameterwhichisnotespeciallypopularintheworksofexpertsinthe?-opticalqualitiesofcleanlayersofP3HTandP3OT,andarerefertotheirresultsinthispaper[8].Thenoveltyandoriginalityoftheworkisrelatedtoundertakingresearchinthe?eldofmaterialpoundsthat?ndapplicationinsuch?,thereareonductivelayers?:..Polymers2018,10,,however,aswehaveexplained,wehaveexpandedthemeasurementtemperaturerangeofblendlayersto130,??,ourworkisapioneerinthestudyofthethermo-?"1and"2,expressedasfunctionsofthephotons’energy[27].Theycanbetransformedintorefractivemonforpresentingresultsinopticalranges[22,28,29].Thebasicparametersoftheelectronicstructureofthepolymerlayersmustbedeterminedbymeansofanappropriateopticalmodeldescribingthebandopticaltransitionsbetweentheexcitedandvalencestates[22,23].Forthispurpose,(A),broadening(Г),energycenter(E0),monenergygap(Eg)[30]?ttedtothespectraldependenciesn(hn)andk(hn),wherenislightfrequency[23,31].Macroscopicparameterssuchas"2(hn)andk(hn)(1)and(2)wepresentthespectraldependenceoftheimaginarypartofdielectricfunction"2(hn)[23].,non-interactingoscillators,theclassicalLorentzoscillatoristhemostnaturalmodelthatcanbeappliedtodescribetheiropticalproperties[30].AccordingtotheLorentzmodel,theimaginarypartofthedielectricfunctionmaybeexpressedas:AE0Ghn"2L(hn)=2.(1)E2(hn)2+G2(hn)20However,inbuildingpolymerstherearemanyresonantstatesresultingfromtheirchainstructure,situatedinsmallspectraldistancesfromeachother[32].(GO).Conjugatedpolymer?lmscanbequotedhereasanexampleoftheproblem[22].Oisgiveninthefollowingequation:"#"#!(hnE)2(hn+E)2"(hn)=Aexpn+expn,(2)2Gnnnwhere:Gnn=p(3)2ln2Ann-thamplitude,Enn-thcenterenergy,Gnn-thbroadeningparameter.:..Polymers2018,10,,theimaginarypartofthedielectricfunction"2Gcanbedescribedbythe?rstexponentappearinginEquation(2).Gaussianoscillatorsadequatelydescribetheopticalpropertiesofconjugatedpolymersinawiderspectralrange().However,itshouldbeunderlinedthatbothmonopticalgapforpolymer?lms[31].Ifthecrystallinityofpolymer?lmsislow,thentheTauc-Lorentzmodel(TL)canbeusedinthe?rstapproximation[33,34].TheTLoscillatorisusedformodellingamorphousandamorphous-likethin?,urinamorphous?-Lorentzmodel,the"2introducedbyJellisonandModine[33]isgivenastheproductoftheTaucfunction"2TLandtheLorentzoscillatorfunctionL(E):2hnEg"2TL(hn)=G,(4)hnwhere:hnisthephotonenergy,Egistheopticalgap,,P3HT,P3OT,andPCMBsolutionspurchasedfromSigmaAldrich(,MO,USA)[35]:PCBM,P3OT:PCBM,andP3HT:P3OT:PCBM(1:1w/w,10mg/mLforpolymer)-15(LOT-OrielGmbH,Darmstadt,Germany),thelayerswereannealedinavacuumfor30minatthetemperatureof60-de?nedthermo-opticalpropertiesinawidetemperaturerange[36].Moreover,ahigherrefractiveindicesdifference(Dn)onthelayer-substrateinterfaceenhancesthesignal-to-noiseratiooftheexperimentaldataandtherebyincreasesthesensitivityoftheellipsometricmeasurement[8,37].Forapolythiophene-Siinterface,,whileforapolythiophene-?,changesofthelightpolarizationduetoitsre?(PsiandDelta),whichponents,parallelandperpendiculartoincidenceplaneofthelight,=exp(iD)tanY(5)(n,k),thickness(d),theangleofincidence(i),andthewavelength()ofthelight:(D=D(n,k,,d,i)(6)Y=Y(n,k,,d,i)Basedonasingleellipsometricmeasurementperformedforselectedanglesofincidence,,twounknownparameterscanbefound,(.,nandk).Performingmeasurementsformanglesofincidence,,thenumberofdeterminedparametersislower,buttheaccuracyandreliabilityofsimultaneous?ttingsofanopticalmodeltoexperimentaldataperformed:..Polymers20
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