第五章-4-有机太阳电池OPV-20141204

OrganicMaterialsforelectronics&Photonics第五章1CdTe太阳电池2CuInGaSe2(CuInS2)太阳电池3染料敏化太阳电池(DSSC)4有机太阳电池(OPV)有机太阳电池(OPV,OrganicPhotovoltaics,OSC,OrganicSolarCellsOPV结构及机理WhyOPV?31OPV制备过程3334OPV发展历程32OPV性能的影响要素35OPV的发展现状及挑战36WhyOPVs?OrganicMaterialsforelectronics&PhotonicsAdvantagesofOPVs-Processedeasilyoverlargearea-spin-coating-doctorbladetechniques(wet-processing)-evaporationthroughamask(dryprocessing)-printing-Lowcost-Lowweight-Mechanicalflexibilityandtransparency-BandgapoforganicmaterialscanbeeasilytunedchemicallybyincorporationofdifferentfunctionalgroupOrganicMaterialsforelectronics&Photonics重量轻成本低WhyOPVs?(Application)OrganicMaterialsforelectronics&PhotonicsWhyOPVs?(Application)WhyOPVs?(Application)OrganicMaterialsforelectronics&PhotonicsOrganicMaterialsforelectronics&PhotonicsRequirementofOPVsSource:SiemensAGOrganicMaterialsforelectronics&PhotonicsHistoryofOPVsOrganicMaterialsforelectronics&Photonics(MgPh,200mV)(Polymer/C60)In2010,SolarmerEnergy,Inc:8.13%;Konarka:8.3%.In2011,MitsubishiChemicalCorp:8.5%;SouthChinaUniverisityofTechnology曹镛院士组：8.37%;2014年8月，10.7%;In2012,Konarka:9%;In2011,Dou,L.etal(UCLA):8.62%NaturePhoton.6,180–185(2012).In2012,Heliatek:10.7%;SumitomoChemicalofJapan:10.6%;InJan2013,Heliatek:12%SingleJunctionSolarCell:TandemSolarCell:OrganicMaterialsforelectronics&Photonics有机太阳能电池的结构glassITOLiFglassADA+DAlOrganicMaterialsforelectronics&PhotonicsOrganicMaterialsforelectronics&PhotonicsOrganicMaterialsforelectronics&PhotonicsOrganicorpolymersingle-layerPVsDisadvantageOrganicMaterialsforelectronics&PhotonicsOrganicMaterialsforelectronics&Photonics有机太阳能电池的基本原理①②③④LightisabsorbedinthepolymerlayerAbsorptioncreatesaboundelectron-holepair(exciton)ExcitonissplitintoseparatechargeswhicharecollectedatcontactsDonorAcceptorOrganicMaterialsforelectronics&PhotonicsOrganicMaterialsforelectronics&PhotonicsOPV制备过程（以体异质结OPV为例）OrganicMaterialsforelectronics&PhotonicsOPV制备过程（以体异质结OPV为例）OrganicMaterialsforelectronics&PhotonicsOrganicMaterialsforelectronics&PhotonicsOrganicMaterialsforelectronics&PhotonicsOrganicMaterialsforelectronics&PhotonicsOrganicMaterialsforelectronics&Photonics有机物成膜：将给体材料(如P3HT)和受体材料（如PCBM）充分溶解、搅拌并过滤后，滴至缓冲层表面上，旋涂成膜。OrganicMaterialsforelectronics&PhotonicsOrganicFilmPreparationOrganicMaterialsforelectronics&PhotonicsOrganicFilmPreparationOrganicMaterialsforelectronics&PhotonicsOPV活性层制备过程阴极溅射或蒸发镀膜：将涂过活性层的电池上贴上高温胶带或者掩模板后，放入磁控溅射仪或者高真空镀膜系统内生长无机缓冲层和金属膜。OPV性能的影响要素给受体材料电极界面修饰形貌控制结构设计OrganicMaterialsforelectronics&Photonics活性层材料——给体材料pentaceneSmallMoleculeDonorsCuPcF16CuPCZnPc**OOMDMO-PPV*S*P3HTNN**PFBPolymerDonorsOrganicMaterialsforelectronics&Photonics受体材料的选择OrganicMaterialsforelectronics&PhotonicsMaterialsforBHJorganicsolarcellC60C70ICBAICMAPC61BMPC71BMPC71HM电极材料的选择阳极：功函数较高且透明或半透明的金属或导电聚合物、导电氧化物。ITO有较高的功函数，在可见光和近紫外区有良好的透过率。阴极：阴极材料主要是功函数较低的金属构成的，如Mg、Al、Ca、Ag，其中Al最为常用。OrganicMaterialsforelectronics&Photonics界面修饰材料阳极界面修饰材料无机界面修饰材料：MoO3、WO2、V2O5等有机界面修饰材料：PEDOT:PSS阴极界面修饰材料无机界面修饰材料：LiF、ZnO、TiO2等有机界面修饰材料：PFNPFN优化器件性能的几个方面：Poly-N-dodecyl-2,5-bis(2´-thienyl)pyrrole-2,1,3-benzothiadiazole:PTPTBthepush-pullconceptbyalteringelectronrichN-dodecyl-2,5-bis(2´-thienyl)pyrroleandelectrondeficient2,1,3-benzothiadiazolegroups1:LowbandgappolymerBandgapengineeringTheparametersdeterminingthebandgapofconjugatedpolymersE∆r:theenergycontributionfrombondlengthalternationRE:theresonanceenergyEΘ:theenergycausedbytheinterringtorsionangleESUB:theinfluenceofthesubstituents.EG=E△r+RE+Eθ+Esub1.Aromatic(芳香族的)formshowshigherstabilizationenergyandthereforethehigherbandgap.2.ResonanceenergyleadstoanenergystabilizationandsotoanincreasedsplittingoftheHOMO-LUMOenergy.3.Torsionbetweentheringplaininterruptstheconjugationandthereforeincreasesthebandgap.4.Electrondonatinggroups(推电子基团)raisetheHOMOlevelandelectronwithdrawinggroups(拉电子基团)lowertheLUMO.5.Inthesolidphase,additionalintermoleculareffectsbetweenthechainshavetobetakenintoaccount,whichgenerallyleadstobroaderbandsandalowerbandgap.OrganicMaterialsforelectronics&PhotonicsSyntheticstrategy1.Introductionofsidegroups:increaseordecreasetheelectrondensity2.Push-pullpolymers:Thebandgapofcopolymerswithalternatingofelectronrichandelectronpoorcompoundscandecreasesignificantly.(ThebondlengthalternationisreducedandsothePeierlsstabilisation.)3.Introductionofmethine(次甲基)groupsbetweentheringsystems:Thequinoid(醌型化合物)formminimizetheinterannularrotationbythedoublebondcharacterofthebridgebondsaswellasthebondlengthalternation.(Thestructurebecomesmoreflatandtheresonancebetweentheringsisincreased.)Potentialdiagramvs.bondlengthalternationfor(a)trans-polyacethyleneasconjugatedpolymerwithdegenerategroundstate;(b)forpolyphenyleneasconjugatedpolymerwithnondegenerategroundstateWhichistheVoc?Isitintheelectrodes?(MIMpicture)VocIsitinthebulk-heterojunction?(p/n-likepicture)Voc2:Originofopen-circuitvoltage(Voc)TOPELECTRODEWORKFUNCTION[eV]Ca2.87Al4.28Ag4.26Au5.1OrganicMaterialsforelectronics&PhotonicsS1S21.Vocinplasticsolarcellisdirectlyrelatedtotheacceptorstrengthofthefullerene.2.Thevariationofnegativeelect