基于激基复合物型双母体磷光有机电致发光器件研制

Research on Phosphorescent Organic Light-emitting Devices based on the exciplex-type co-host

摘要:

利用电子给体材料mTPA-PPI和电子受体材料PO-T2T,实现了一种具有显著热活化延迟荧光特性的激基复合物,通过时间分辨谱技术,探明了mTPA-PPI:PO-T2T间激子的反系间窜越(Reverse Intersystem Crossing,RISC)、瞬时荧光、延迟荧光等激子动力学过程；研制了基于mTPA-PPI:PO-T2T双母体的高性能磷光OLED器件,通过高效的反系间窜越过程,提升了三线态激子的利用率,有效提高了器件效率,缓解了高电流密度下的效率滚降。基于激基复合物双母体红光磷光器件的最大电流效率、功率效率、外部量子效率分别为20.3 cd/A、18.6 lm/W、11.54 %,是单母体器件的1.4、1.2、1.5倍,此外,双母体器件的最高亮度高达25410 cd/m₂^,是单母体器件最高亮度的3.9倍。

Abstract:

A highly efficient exciplex with significant thermally activated delayed fluorescence characteristics was realized by combining the electron donor of mTPA-PPI and the electron acceptor of PO-T2T. The exciton dynamics processes, such as the reverse Intersystem crossing (RISC), prompt fluorescence, and delayed fluorescence of mTPA-PPI:PO-T2T were explored through the time-resolved spectra technology. A high-performance phosphorescent OLED based on the mTPA-PPI:PO-T2T co-host was developed. Due to an efficient reverse intersystem crossing process, the triplet exciton utilization was improved, effectively boosting device efficiency and alleviating efficiency roll-off at high current densities. The maximum current efficiency, power efficiency, and external quantum efficiency of the red phosphorescent device based on the co-host were 20.3 cd/A, 18.6 lm/W, and 11.54 %, respectively, which were 1.4, 1.2, and 1.5 times that of single-host device. Significantly, the maximum luminescence of the co-host device reached 25410 cd/m², which was 3.9 times that of the maximum luminescence of a single-host device.