单层有机发光二极管中复合区域和外量子效率的研究

325*∗11,21,1,111(1.4100822.410083)*No.03JJY10082004-02-271979E-mail:[e-mail](1)(2)OLEDsTN873.3A1001-97312004-0325-031(OLEDs)EL[1~3][4]ELPL[5]EL[6]LB[7][8]2τrec[8]w=µhFτrec1τrec=(γne)-12µhγeF=V/d,Vdj=e(µene+µhnh)F3µhµee≈hne≈j/eµhF,w=eµh2F2/γjLangevinγ=e(µe+µh)/εε0≈eµh/εε04w=µhεε0F2/j5Onsagerj=AF3/4exp(aF1/2)6Aa=(e/kT)(e/4πεε0)1/2Schottkyeε0εµhµ0hexp(βuF1/2)βuF0-1/2µ0hβuw=µ0hεε0/AF4/5exp[(βu-a)F1/2]7PR,PR=PR(1)PR(2)=[1+(τm/τt)]-1[1+(τc/τd)]-1=(1+w/d)-1Pr,τmτtτcτdPr1(aP1+bP2)P3P1P2P3[9]φELφEL=ξPRPsφr=ξPsφr(1+w/d)-1Pr8ξ[4]ξ1/2n2Ps326200435Ps0.25φr0.25T=300Kε=3.0d=100nmn=1.7u0h=5×10-6(cm2/v·s)33.1PR=(1+w/d)-1Pr[4]//9V20nmFig1Thewidthofrecombinationzonevs.appliedvoltageinsinglelayerOELDs3.22Ec2Fig2Externalquantumefficiencyvs.appliedvoltageinsinglelayerOLEDswithdifferentthicknesses3[10]Fig3Thecomparisonbetweenthemodelandthedatuminreference10310624ITO/(50%TPD:30%Alq3:20%PC)(60nm)/MgITO/(25%TPD:32725%Alq3:50%PC)(80nm)/Mg60nm80nmA10-83×10-92.2MV/cm[10]/[10]4(1)(2)[1]ShizuoTokito,ToshikiIijima,YoshiyukiSuzuri.Confinementoftripletenergyonphosphorescentmoleculesforhighly-efficientorganicblue-light-emittingdevices[J].ApplPhysLett,2003,83(3):569-571.[2]LiaoLS,KlubekKP,TangCW.High-efficiencytandemorganiclight-emittingdiodes[J].ApplPhysLett,2004,84(2):167-169.[3]XieZYandHungLS.High-contrastorganiclight-emittingdiodes[J].Appl.Phys.Lett.,2004,84(7):1207–1209.[4]KalinowskiJ,PalilisLC,KimWH,etal.Determinationofthewidthofthecarrierrecombinationzoneinorganiclight-emittingdiodes[J].JApplPhy.,2003,94(12):7764-7767.[5]KalinowskiJ.Space-resolvedrecombinationelectroluminescenceinorganiccrystals[J].SynthMet,1994,64(2-3):123-132.[6]VestweberH,BässlerH,GrünerJ,etal.SpatialextentoftherecombinationzoneinaPPV/polymerblendlight-emittingdiode[J].ChemPhysLett,1996,256(1-2):37-42.[7]GrünerJ,RemmersMandD.Neher.Directdeterminationoftheemissionzoneinapolymerlight-emittingdiode[J].AdvMater,1997,9(12):964–968.[8]KalinowskiJ,MurataH,PiccioloLC,etal.Voltageevolutionoftherecombinationzoneandemissionquantumyieldinorganiclight-emittingdiodeswithdopedandundopedemitterlayers[J].JPhysD:App.Phys,2001,34(8):3130-3138.[9]LiHJ,PengJC,XuXM,etal.Theefficiencyoftheformationandfissionofpolaron-excitonsinpolymerlightemittingdevices[J].ActaPhysicaSinica,2001,50(11):2247-2251(inChinese).[10]KalinowskiJ,CocchiM,GiroG,etal.Injection-controlledelectroluminescenceinorganiclight-emittingdiodesbasedonmolecularly-dopedpolymers:I.Single-layerdevices[J].JPhysD:ApplPhys,2001,34(6):2274-2281.InvestigationoftherecombinationzoneandexternalquantumefficiencyinsinglelayerOLEDsZHAOChu-jun1,LIHong-jian1,2,CUIHao-yang1,DAIGuo-zhang1,HUANGYong-hui1,XIEQiang1,PENGJing-cui1(1.DepartmentofAppliedPhysics,HunanUniversity,Changsha410082,China;2.StateKeyLaboratoryforPowderMetallurgyCentralSouthUniversity,Changsha410083,China)AbstractAnanalyticalmodeltocalculatethewidthofrecombinationzoneandtheexternalquantumefficiencyinsinglelayerOLEDswaspresented,inwhichtherecombinationprobabilitywasdefinedastheaproductoftheprobabilityofformationoftheexcitonsandtheprobabilityofitsconversionintotheexcitedsingletortripletstates.Theinfluencesofappliedbiasandthethicknessofthedeviceonthewidthofrecombinationzoneandtheexternalquantumefficiencywerethoroughlystudied.Thetheoreticalmodelcouldgetgoodresultscomparedwiththerelatedliterature.KeywordsrecombinationzoneexternalquantumefficiencyOLEDs