Very High Efficiency Orange-Red Light-Emitting Devices with Low Roll-Off at High Luminance Based on an Ideal Host-Guest System Consisting of Two Novel Phosphorescent Iridium Complexes with Bipolar Transport
Very High Efficiency Orange-Red Light-Emitting Devices with Low Roll-Off at High Luminance Based on an Ideal Host-Guest System Consisting of Two Novel Phosphorescent Iridium Complexes with Bipolar Transport
复制标题
基于由两种具有双极传输的新型磷光铱配合物组成的理想主客体系统的高亮度低滚降的非常高效橙红色发光器件
DOI：
10.1002/adfm.201402177
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发表时间：
2014
影响因子：
19
通讯作者：
Bryce Martin R.
中科院分区：
文献类型：
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作者：
Li Guomeng;Zhu Dongxia;Peng Tai;Liu Yu;Wang Yue;Bryce Martin R.
合成了两种具有双极输运能力的磷光铱配合物FPPCA（500 nm）和BZQPG（600 nm），并将其用作磷光有机发光二极管（PHOLED）的理想主-客体系统。该器件从BZQPG获得非常高效的橙子-红色发射，具有最大的外量子效率（EQE或ηext）>27%，最大功率效率（PE或ηp）>75 lm/W，并在1000和5000 cd m−2的高亮度下分别保持26%和55 lm/W，25%和40 lm/W的高水平，BZQPG的含量在8-15重量%的范围内。这种高且稳定的EL性能的实现是由于两种平行路径的共存：i）从主体（FPPCA）到客体（BZQPG）的有效能量转移和ii）在BZQPG发射体上的直接激子形成，其可以交替地主导电致磷光发射。由于两种磷光体固有的窄Eg，这种全磷光体掺杂系统消除了从电荷传输过程到发射层（EML）的电荷注入势垒。因此，这种理想的主-客体系统代表了一种新的设计，可以使用简单的器件配置来生产具有高效率和低效率滚降的PHOLED。
Two phosphorescent iridium complexes with bipolar transporting ability, namely FPPCA (500 nm) and BZQPG (600 nm), are synthesized and employed as an ideal host‐guest system for phosphorescent organic light emitting diodes (PHOLEDs).The devices give very high‐efficiency orange‐red emission from BZQPG with maximum external quantum efficiency (EQE orηext) of >27% and maximum power efficiency (PE orηp) of >75 lm/W, and maintain high levels of 26% and 55 lm/W, 25% and 40 lm/W at high luminance of 1000 and 5000 cd m−2, respectively, within a range of 8–15 wt% of BZQPG. The realization of such high and stable EL performance results from the coexistence of two parallel paths: i) effective energy transfer from host (FPPCA) to guest (BZQPG) and ii) direct exciton formation on the BZQPG emitter, which can alternately dominate the electrophosphorescent emission. This all‐phosphor doping system removes the charge‐injection barrier from the charge‐transport process to the emissive layer (EML) due to the inherent narrowEgof both phosphors. Therefore, this ideal host–guest system represents a new design to produce PHOLEDs with high efficiency and low efficiency roll‐off using a simple device configuration.