双层阴极结构BaOAl聚合物电致发光器件电子注入的研究

44()Vol.44Sup.20056JournalofXiamenUniversity(NaturalScience)Jun.2005BaO/Al:2005201212:863(2001AA313070):(1977-),,.1,1,2,3,1(1.,361005;2.,360000;3.,510640):BaO/AlMEH2PPV(PLEDs),BaO.,BaO,Al,2010,1250cd/m20.4%.BaO,,,1nm.,LiFCsF,,BaO,BaOBa.:;;:O433.4:A:043820479(2005)Sup20326204(PLEDs),.,(ITO),.,,,,BaMg:Ag[1]Ca[2],,[1],.,Al.,AlBaCaMg:Ag.,Al,LiFSiO2CsF,[38].BaO/Al,(PPV)MEH2PPV,BaO.,BaO,BaO1nm,Al.,BaO,.1PLEDMEH2PPVPLEDITO/PE2DOT/MEH2PPV/BaO/Al,1.poly(eth2ylendioxythiophene):poly(styrenesulfonicacid)(PEDOT:PSS).ITO10min,80,ITO,.ITOPEDOT,8012h,80nmMEH2PPV.BaO(10-4Pa)Ba,10min,BaBaO,,160nmAl,Al.0.15cm2.1MEH2PPVFig.1ThechemicalstructureofMEH2PPVandthestructureofPLEDAlfaStep2500.I2VKeithley2362©1994-2006ChinaAcademicJournalElectronicPublishingHouse.Allrightsreserved.,BaO,BaOFig.2CharacteristicsandelectroluminescenceofBaO/Al()andAl()PLED(a)Luminanceandvoltage,(b)Externalquantumefficiency,,(EL)Instaspec4CCD,PR705..4BaO2(a)2(b)I2V(c)Fig.4EffectsofBaOthicknessvariationontheI2VcharacteristicsandelectroluminanceofPLEDs(a)Luminanceandvoltage;(b)Externalquantumefficiency;(c)I2Vcharacteristics22(a)BaOBaOPLED2,2(b)2,BaO1nm.2(a)(turn2onvoltage),2.2V.BaO,Al,20,10.8V,BaO/Al1250cd/m2,Al60cd/m2.3I2V,,BaO.BaO,,,MEH2PPV,.,2,.32,BaO,BaOFig.3I2VcharacteristicsofBaO/Al()andAl()PLEDBaO,BaOPLED,4.,BaO,BaO,;1nm,,1250cd/m20.4%;BaO1nm,723:BaO/Al©1994-2006ChinaAcademicJournalElectronicPublishingHouse.Allrightsreserved.(a),(b),+Fig.5Schematicenergybandmodelatacertainforwardbiastoillustratetheelectroluminescencecharac2teristicsofthedeviceswithout(a)andwith(b)insulatinglayer(BaO),10nm.QuocToanLe[6]PongpunPiromreun[7]LiFCsFPLED,LiFCsFLiCs[7].BaO,,,.,BaO,BaOBa.MEH2PPV,(LUMO)(HOMO)2.8eV4.9eV.Al4.3eV,1.5eV,0.3eV(PEDOT:PSSHOMO5.2eV),5(a).,.BaO,,BaO,,,MEH2PPV,,5(b),,,,.KimLiF,,,,[3].,BaOLiF,.BaO(0.5nm),,.1nm,,BaO,,,,4(c),10nm,,.PongpunPiromreunCsF,CsF,,[7].,BaO,.,,.BaO,[8].3AlBaO/Al,BaO.,AlBaO,,Al2010.,BaOBa,BaO,BaO,BaO,,,,PongpunPiromreunCsF,BaO.,BaO,,..:[1]TangCW,VanSlykeSA.Organicelectroluminescentdi2odes[J].Appl.Phys.Lett.,1987,51:913-915.[2]ChoongVE,MasonMG,TangCW,etal.Investigationoftheinterfaceformationbetweencalciumandtris2(82hydroxyquinoline)aluminum[J].Appl.Phys.Lett.,1998,72:2689-2691.[3]KimYE,ParkH,KimJJ.Enhancedquantumefficiencyinpolymerelectroluminescencedevicesbyinsertingatun2nelingbarrierformedbyLangmuir2Blodgettfilms[J].Ap2pl.Phys.Lett.,1996,69:599-601.[4]KimHH,MillerTM,WesterwickEH,etal.Siliconcompatibleorganiclightemittingdiode[J].J.LightwaveTechnol.,1994,12:2107-2113.[5]LiF,TangH,AndereggJ,etal.Fabricationandelectrolu2minescenceofdouble2layeredorganiclight2emittingdiodeswiththeAl2O3/Alcathode[J].Appl.Phys.Lett.,1997,823()2005©1994-2006ChinaAcademicJournalElectronicPublishingHouse.Allrightsreserved.:1233-1235.[6]LeQuocToan,YanLi,GaoYongli,etal.Photoemissionstudyofaluminum/tris2(82hydroxyquinoline)aluminumandaluminum/LiF/tris2(82hydroxyquinoline)aluminuminterfaces[J].J.Appl.Phys.,2000,87:375-379.[7]PiromreunPongpun,OhHwanSool,ShenYulong,etal.RoleofCsFonelectroninjectionintoaconjugatedpoly2mer[J].Appl.Phys.Lett.,2000,77:2403-2405.[8]StoesselM,WittmannG,StaudigelJ,etal.Cathode2in2ducedluminescencequenchinginpolyfluorenes[J].J.Ap2pl.Phys.,2000,87:4467-4475.StudyofElectronInjectionofPolymerLight2emittingDeviceswithaBilayerCathodeofBaO/AlZHANGWei1,HUANGMei2chun1,LIUYin2chun2,XUYun2hua3,ZENGYong2zhi1(1.DepartmentofPhysics,XiamenUniversity,Xiamen361005,China;2.FujianAgriculturalandForestryUniversity,Fuzhou350002,China;3.InstituteofPolymerOptoelectronicMaterialsandDevices,SouthChinaUniversityofTechnology,Guangzhou510640,China)Abstract:TheeffectofthebilayercathodeBaO/Alonelectroninjectioninapolymerlight2emittingdiode(PLED)deviceispres2ented.ThedeviceshaveaBaO/AlbilayerasacathodeandaMEH2PPVasalight2emittinglayer.Itisshownthatinourexperiments,theelectroninjectionwasimprovedbyinsertingtheinsulatinglayerBaObetweenAlandMEH2PPV.Theluminanceandefficiencywere20and10timestothedeviceswithsingleonlyAlasacathode,reaching1250cd/m2and0.4%.Wealsoinvestigatedthede2pendenceofelectroninjectiononthethicknessoftheBaOlayer.Withincreasingthethicknessoftheinsulatinglayer,theexternalquantumefficiencyandluminancewereincreasingatfirst.Asthethicknessarrivedtoabout1nm,theybegantodecrease.Sotheopti2mumthicknessforBaOlayerwas1nm.Inaddition,ourresultsonBaOhavebeencomparedwithsomeofLiFandCsFastheinsula2tinglayerfabricatedbytheotherresearchgroup.ItprovedthattheelectroninjectionenhancementdependsontheinsulatingBaOlayerandnotduetothemetallicBadecomposedfromBaO.Keywords:polymerlightemittingdevices;theinsulatinglayer;tunnelingcurrent923:BaO/Al©1994-2006ChinaAcademicJournalElectronicPublishingHouse.Allrightsreserved.