有机电致发光器件中观察到的三重态-三重态湮灭导致的荧光发射
第28卷第3期
2007年6月
发光
CHINESEJOURNAL
OFLUMINESCENCE
V01.28No.3
Jun,,2007
DirectObrvationofEnhancedElectrofluorescence EmissionthroughTriplet—tripletAnnihilationin OrganicLight—emittingDevices
suWen—ming,LIWen.1ian,KONGZhi—guo'
ZHUJian—zhuo.Y ANGDong—fang'
(1.KeyLaboratoryofExcitedStateProcess,ChangchunInstittaeofOptics,FineMechanic sandPhysics,
ChineAcademyofSciences,Changchna130033,China;
2.GraduateSchooloftheChineAcademyofSciences,Beijing100049,China) Abstract:WithN,N'-dimethyl.quinacridone(DMQA)heavilydopedintotris-(8-hydroxyq uinoline)aluminum
(A1q1)鹪emissionlayer,asuper-linearluminanceenhancementwiththeincreaofcurrentdensityino rganmlight.
emittingdeviceswasobrved.When【heconcentrationofDMQAwasI.6%～5.6%(inmassfraction)andthecur-
rentdensitvexcess300mA/cm,contrarytotheroll.offinelectroluminescence(EL)efficienc
y,theELefficiency
ascendswit}Icun℃ntdensity.About～0.22cd/AenhancedELefficiencyisobrvedfrom300mA/cm~to700mA/cm", whichisbelievedtobecontributedtotheextraregeneratedsingletexcitonsresultedfromT-Ta nnihilation.
Key
CLC
words:T一T'annihilation;DMQA;OLEDs
number:TN383.IPACC:7860FDocumentcode:AArticleID:1000-7032(2007)03-043"7-03
Recentstudies[,]ofphosphorescencefromor. ganicmoleculeshaveopenedanewwayforhighly
发簪efficientELdevices.Onesignificantissueofelectro- phosphorescentdevicesisthedecreainexternal quantumefficiencywithincreasingcurrentdensity,
tion【』.
T.Tannihilation,namely,istripletex- citedstatesgothroughannihilativereactionswith othertripletexcitedmoleculestoformsingletexcited
states【4.
.
Influorescentdevices.theexcitonsare formedintheratioofonesinglettothreetriplets duringELprocessthoughthetripletsisnotdirectly contributetolightemissionbecauofspincon—
fine[.
T.T'annihilationhadbeenassumedtobe
applicableforAlq3一badelectrofluorescentde'
vices[引
.
butthereisnoexperimentalinformationof
T.T'annihilationintheELemissionoffluorescent
dyedopedAlq3device.Inthiswork,weemployed
AlqashostandN,N'-Dimethyl-quinacridone
(DMQA)asFt~rsterenergyacceptorfortheOLEDs
emissionlayer,thephenomenaofcurrentefficiency ascendswithcurrentdensitywasobrvedasDMQA
concentrationmoret}lall1.6%andthecurrentden-双合汤
环顾的意思
sityexceeds300mA/cm2.
Alldeviceswerefabricatedbythermaldeposi—
tioninhighvacuumof5x10一Paduringonepump
down.ITO.glasswithsheetresistanceof20r口
wasudassubstrate.Priortou,thesubstrates werecleanedbyultrasonicindetergentsolution,
distilledwater,andacetone,followedbytreatment
of0.plasmafor3minthen1oadedintovacuum
期颐怎么读
theanode.Thecharacteristicsofluminance—current
Receiveddate:2007-02-20;Reviddate:2007-03-16
Foundationitem:ProjectsupportedbytheNationalNaturalScienceFoundationofChina(90 201012)
Biography:SUWen.ming,male,wasbornin1978,HunanProvince,Doctor.Hisworkfocu sonorganicelectmluminescenee
E-mall:aue.._
wenminyahoocorncn
}:CorrespondingAuthor;E-mail:*****************.an,Tel:(0431)86176345
438发光第28卷density—ombinedwith KEITHLEY2000Muhimeterinairatroomtempera—
体育竞技
ture.TheELspectraweredetectedbyaCCDspec—trometer.
Fig.1showsthechemicalstructuresofmate. rialsandthedeviceconfiguration,whereNPB,4,
4'-bis[N一(1一naphthy1)一N—phenyl—amino]biphenyl, isudasholetransportlayer,Alq3isudforboth hostandelectrontransportlayer.DMQAdopedAlq3 actsamitterlayer,1nmLiFand100nmA1are rvedalectroninjectionlayerandcathode,re—spectively.
DMQA
Fig.1Con_figurationofthedeviceandchemicalstructuresof materials.
Fig.2showsthecurrentefficiencyus.current densitycharacteristicsof1.6%(inmassfraction) DMQAdopeddeviceandundopeddevice.Itsug- geststheELefficienciesofundopeddevicesdrops monotonouslywithincreasingcurrentdensity.To
1.6%DMQAdopeddevice.theELefficiencystops todeclineasthecurrentdensityincreasuDtoabout Currentdensity/(A?cm-2)
Fig.2Thecurrentefficiencyus.currentdensitycharacteristics. 200mA/cmandevenkeepsincreasingunderhigher currentdensityregion.Similarphenomenonwasalso obrvedin5.6%DMQAdopeddevice. Accordingtothepreviousreport7j.
移动刷钻最新代码
thenonra—
diativelossindeviceofNPB/Alq3aredominated bysinglet—singlet(S一S)annihilation,canbeex—presdasr/l:1/2kss[S](wherekssisthe annihilationconstant,and[S]isthedensityof singlet),leadingtotheefficiencyroll—offinOLED devices.DMQAdopedintoemitterlayeractsas
F6rsterenergyacceptorandreducesthesingletden—sityinhost,conquentlythenonradiativeloss wereeffectivelyalleviated.T.Tannihilationre. suhsinnewbornsinglet
lightemission.Itshould nonradiativelossoverwhe
鬼吹灯结局是什么,whichwillcontributeto
bepointedout,therious lmthepositivecontribution
fromT一Treactioninnon—dopeddevice,thereby theefficiencyroll—offwasobrved,whichwasin—verdin1.6%dopeddeviceandELefficiency ascendswithcurrentdensity.
Fig.3plotstheELefficiencywithcurrentden—sityfordevicesdopedwith1.6%and5.6%DMQA intheregionofhighcurrentdensity(>200mA/ cm).Theefficiencyascendsabout～0.22cd/A areobrvedfro
财政政策货币政策mcurrentdensityof300mA/cmto 700mA/cmf0rb0thdevices.ItindicatestheEL efficiencydataarefittedwithaquadraticfunction, wellconsistentwiththerateofT一Tannihilation, equalsto1/2kT],andthedensityofTis proportionaltocurrentdensity.
