Earmme Taeshik
Department of Chemical Engineering, Hongik University, 94 Wausan-ro, Mapo-gu, Seoul 04066, Korea.
Materials (Basel). 2021 Jan 24;14(3):554. doi: 10.3390/ma14030554.
Solution-processed blue phosphorescent organic light-emitting diodes (PHOLEDs) based on a single emission layer with small-molecule hole-transport materials (HTMs) are demonstrated. Various HTMs have been readily incorporated by solution-processing to enhance hole-transport properties of the polymer-based emission layer. Poly(-vinylcarbazole) (PVK)-based blue emission layer with iridium(III) bis(4,6-(di-fluorophenyl)pyridinato-,C2')picolinate (FIrpic) triplet emitter blended with solution-processed 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC) gave luminous efficiency of 21.1 cd/A at a brightness of 6220 cd/m with an external quantum efficiency (EQE) of 10.6%. Blue PHOLEDs with solution-incorporated HTMs turned out to be 50% more efficient compared to the reference device without HTMs. The high hole mobility, high triplet energy of HTM, and favorable energy transfer between HTM blended PVK host and FIrpic blue dopant were found to be important factors for achieving high device performance. The results are instructive to design and/or select proper hole-transport materials in solution-processed single emission layer.
展示了基于具有小分子空穴传输材料（HTM）的单发射层的溶液处理蓝色磷光有机发光二极管（PHOLED）。通过溶液处理已容易地掺入各种HTM以增强基于聚合物的发射层的空穴传输性能。含有铱（III）双（4,6 - （二氟苯基）吡啶基 - ，C2'）吡啶甲酸酯（FIrpic）三线态发射体并与溶液处理的1,1 - 双[（二 - 4 - 甲苯基氨基）苯基]环己烷（TAPC）共混的聚（乙烯基咔唑）（PVK）基蓝色发射层在6220 cd/m²的亮度下发光效率为21.1 cd/A，外量子效率（EQE）为10.6%。与没有HTM的参考器件相比，含有溶液掺入HTM的蓝色PHOLED的效率提高了50%。发现HTM的高空穴迁移率、高三线态能量以及HTM共混的PVK主体与FIrpic蓝色掺杂剂之间有利的能量转移是实现高器件性能的重要因素。这些结果对于在溶液处理的单发射层中设计和/或选择合适的空穴传输材料具有指导意义。
