A simple systematic design of phenylcarbazole derivatives for host materials to high-efficiency phosphorescent organic light-emitting diodes
作者:Lin-Song Cui、Shou-Cheng Dong、Yuan Liu、Qian Li、Zuo-Quan Jiang、Liang-Sheng Liao
DOI:10.1039/c3tc30410h
日期:——
A series of novel blue phosphorescent host materials, namely, CTP-1, CTP-2 and CTP-3 have been designed and synthesized through the Suzuki–Miyaura cross-coupling reaction between N-phenylcarbazole and biphenyl. Their thermal, photophysical and electrochemical properties were systematically investigated. These novel hosts show excellent thermal stability and high glass transition temperatures (Tg) ranging from 113 to 127 °C. The triplet energies of these three materials are significantly higher than that of (4,4′-bis(N-carbazolyl)-2,2′-biphenyl) (CBP, 2.56 eV) and that of the most popular blue phosphorescent material iridium(III) bis[(4,6-difluorophenyl)pyridinato-N,C2′] picolinate (FIrpic, 2.65 eV). These three novel materials have superior thermal and electronic properties for blue and white phosphorescent OLEDs. Blue emitting devices with an Ir-complex FIrpic as the phosphorescent dopant have been fabricated and show high efficiency with low roll-off. In particular, 40.4 cd A−1 at 100 cd m−2 and 38.2 cd A−1 at 1000 cd m−2 were achieved when CTP-1 was used as the host material. On the basis of this work, an all-phosphor white device with a current efficiency of 64.5 cd A−1 at 100 cd m−2 and 61.9 cd A−1 at 1000 cd m−2 has also been fabricated.
通过N-苯基咔唑和联苯之间的Suzuki-Miyaura交叉偶联反应,设计并合成了一系列新型蓝色磷光主体材料,即CTP-1、CTP-2和CTP-3。系统地研究了它们的热、光物理和电化学特性。这些新型主体表现出优异的热稳定性和 113 至 127 °C 的高玻璃化转变温度 (Tg)。这三种材料的三重态能量明显高于(4,4'-双(N-咔唑基)-2,2'-联苯)(CBP, 2.56 eV)和最流行的蓝色磷光材料铱的三重态能量( III) 双[(4,6-二氟苯基)吡啶基-N,C2']吡啶甲酸(FIrpic, 2.65 eV)。这三种新型材料对于蓝色和白色磷光 OLED 具有优异的热性能和电子性能。以 Ir 络合物 FIrpic 作为磷光掺杂剂的蓝色发射器件已被制造出来,并且表现出高效率和低滚降。特别是,当使用 CTP-1 作为主体材料时,在 100 cd m-2 下实现了 40.4 cd A-1 ,在 1000 cd m-2 下实现了 38.2 cd A-1 。在此工作的基础上,还制备了一种全荧光粉白光器件,其电流效率在100 cd m−2 时为64.5 cd A−1,在1000 cd m−2 时电流效率为61.9 cd A−1。