Electrophosphorescence from a polymer guest-host system with an iridium complex as guest: Forster energy transfer and charge trapping
Electrophosphorescence from a polymer guest-host system with an iridium complex as guest: Forster energy transfer and charge trapping
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DOI：
10.1002/adfm.200304334
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发表时间：
2003-06-01
影响因子：
19
通讯作者：
Heeger, AJ
中科院分区：
文献类型：
--
作者：
Gong, X;Ostrowski, JC;Heeger, AJ
本文报道了以三[9,9-二己基-2-（苯基-4'（-吡啶-2 ' -基））芴]铱（III） (Ir（DPPF)(3)）为客体，聚维羟基咔唑（PVK）与2-叔丁基苯基-5-联苯-1,3,4-恶二唑（PBD）为主体的混合物制备的高效绿色电磷光发光二极管。电磷光发射具有Ir(DPPF)(3)的特征，在550 nm处达到最大值。在Ir（DPPF）浓度为1 wt.%时，每个电子的外量子效率为8%，发光效率为29 cd A(-1)，最大亮度为3500 cd m(-2)(3)。即使在最低浓度的Ir(DPPF)(3) （0.1 wt.-%）下，器件也没有显示PVK或PBD的发射。结果表明，在这些装置中，福斯特能量转移在实现高效率方面起着次要作用。直接电荷捕获似乎是主要的操作机制。
We report high-efficiency green electrophosphorescent light-emitting diodes obtained by using tris[9,9-dihexyl-2-(phenyl-4'(-pyridin-2"-yl))fluorene]iridium(III) (Ir(DPPF)(3)) as the guest, and a blend of poly(vihylcarbazole) (PVK) with 2-tert-butylphenyl-5-biphenyl-1,3,4-oxadiazol (PBD) as the host. The electrophosphorescent emission is characteristic of Ir(DPPF)(3), with its maximum at 550 nm. An external quantum efficiency of 8 % photons per electron and luminous efficiency of 29 cd A(-1), with maximum brightness of 3500 cd m(-2), were achieved at 1 wt.% concentration of Ir(DPPF)(3). The devices exhibited no emission from PVK or PBD, even at the lowest concentration of Ir(DPPF)(3) (0.1 wt.-%). The results indicate that Forster energy transfer plays a minor role in achieving high efficiencies in these devices. Direct charge trapping appears to be the main operating mechanism.