中科院有机发光二极管 磷光材料

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1、2.7磷光电致发光材料•在光致发光中磷光量子产率比荧光量子产率低。•电致发光材料中，由电子和空穴的复合发光，不受自旋选律的限制，理论上按照统计分布计算，产生激发三重态和激发单重态的比例应该是3:1。1hole(+)electron(-)exciton(*)3symmetricstatesTriplets++or1/+2sitrngiplelett1antisymmetricstate1/-2Singlet3铂金属配合物的电致发光60-Ålayerofcopperphthalocyanineho

2、leinjection350-Å-thicklayeroftheholetransportingmaterial4,4΄-bis[N-(1-napthyl)-Nphenyl-amino]biphenyl(α-NPD)不同浓度的PtOEP器件的外量子效400-Å-thicklayerofAlq3dopedwithvaryingmolar率都随着电流密度的增大而减小，concentrationsofPtOEP100-Å-thicklayerofAlq3topreventquenchingofPtOEP

3、激发的三重态到基态的辐射跃迁发excitonsatthecathode.射磷光的速度较慢，容易导致激发PtOEP在低浓度掺杂的情况三重态的饱和，而出现三重态-三重时均出现了Alq3的发射峰。态的淬灭，使在高电流密度和低掺4Nature1998395151杂浓度的情况下外量子效率降低。•允许但重态到三重态的能量传递的Dexter过程是激子从主体到客体的固有传递过程，其速率正比与主体和客体的轨道重叠程度，是短程过程。当掺杂浓度太低的时候，局部激发的Alq3与PtOEP之间的距离超过Dexter能量传递

4、发生的长度，增加了Alq3的自身发光的几率，这也是磷光掺杂的浓度通常大于荧光掺杂的浓度的原因。5DCM2α-NPDTwoelectroluminescentdevicesdemonstratingthatAlq3tripletsaretransferredtoPtOEP.Eachdevicecontainsa100A°thicklayerof1%DCM2inAlq3attherecombinationzone.Thislayeractstoremovesingletstates.Remaining

5、singletsrecombineinAlq3,yieldingtheshoulderapparentinthespectraat530nm.Device2containsanadditionallayerof10%PtOEPinAlq3positioned200A°awayfromtheAlq3/a-NPDinterface.StrongemissionisseenfromthePtOEPwithoutacorrespondingdecreaseinemissionfromDCM2orAlq3.

6、Thespectraweremeasuredatacurrentdensityof6mA·cm-2.(DCM2is[2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene]propane-dinitrile.)磷光掺杂的有机电致发光器件可以充分利用激发三重态，提高器件的外量子效率。6从电荷注入到三线态激子的形成过程7LigandcenteredexcitationThe

7、lowestexcitedstatesaredetermineddominantlybyMOswhichcanbewelldescribedbytheπ-HOMOandtheπ*-LUMOoftheorganicligands.Theseorbitalsandtheirenergiesaresomewhatalteredbycoordinationoftheligand(s)tothepositivelychargedmetal.Usually,thisleadstoaredshift(i.e.,

8、ashifttolowerenergy)ofthecorrespondingtransitionsoftheorderof103cm−1(≈0.12eV).Metalcenteredexcitation1.Compoundswiththesameligandsandthesamecentralmetalionexhibita40–80%Dqincrease,whenthemetaloxidationchangesfrom2+to3+.2.Compoundswiththesameli