School of Chemistry and Chemical Engineering, Queen's University , Belfast BT7 1NN, U.K.
Shanghai Taoe Chemical Technology Co., Ltd , Shanghai 200030, PR China.
ACS Appl Mater Interfaces. 2018 Feb 14;10(6):5714-5722. doi: 10.1021/acsami.7b18202. Epub 2018 Feb 5.
The electron-accepting [1,2,4]triazolo[1,5-a]pyridine (TP) moiety was introduced to build bipolar host materials for the first time, and two host materials based on this TP acceptor and carbazole donor, namely, 9,9'-(2-([1,2,4]triazolo[1,5-a]pyridin-2-yl)-1,3-phenylene)bis(9H-carbazole) (o-CzTP) and 9,9'-(5-([1,2,4]triazolo[1,5-a]pyridin-2-yl)-1,3-phenylene)bis(9H-carbazole) (m-CzTP), were designed and synthesized. These two TP-based host materials possess a high triplet energy (>2.9 eV) and appropriate highest occupied molecular orbital/lowest unoccupied molecular orbital levels as well as the bipolar transporting feature, which permits their applicability as universal host materials in multicolor phosphorescent organic light-emitting devices (PhOLEDs). Blue, green, and red PhOLEDs based on o-CzTP and m-CzTP with the same device configuration all show high efficiencies and low efficiency roll-off. The devices hosted by o-CzTP exhibit maximum external quantum efficiencies (η) of 27.1, 25.0, and 15.8% for blue, green, and red light emitting, respectively, which are comparable with the best electroluminescene performance reported for FIrpic-based blue, Ir(ppy)-based green, and Ir(pq)(acac)-based red PhOLEDs equipped with a single-component host. The white PhOLEDs based on the o-CzTP host and three lumophors containing red, green, and blue emitting layers were fabricated with the same device structure, which exhibit a maximum current efficiency and η of 40.4 cd/A and 17.8%, respectively, with the color rendering index value of 75.
首次引入了电子受体[1,2,4]三唑并[1,5-a]吡啶（TP）部分，构建了基于此 TP 受体和咔唑供体的两个双极主体材料，即 9,9'-(2-([1,2,4]三唑并[1,5-a]吡啶-2-基)-1,3-亚苯基)双(9H-咔唑)（o-CzTP）和 9,9'-(5-([1,2,4]三唑并[1,5-a]吡啶-2-基)-1,3-亚苯基)双(9H-咔唑)（m-CzTP）。这两种基于 TP 的主体材料具有高三重态能量（>2.9 eV）和适当的最高占据分子轨道/最低未占据分子轨道能级以及双极传输特性，使其可作为多色磷光有机发光器件（PhOLEDs）的通用主体材料。基于 o-CzTP 和 m-CzTP 的蓝色、绿色和红色 PhOLED 采用相同的器件结构，均表现出高效率和低效率滚降。基于 o-CzTP 的器件分别显示出蓝色、绿色和红色发光的最大外量子效率（η）为 27.1%、25.0%和 15.8%，与基于 FIrpic 的蓝色、基于 Ir(ppy)的绿色和基于 Ir(pq)(acac)的红色 PhOLED 的最佳电致发光性能相当，这些器件采用单一组分主体。基于 o-CzTP 主体和包含红色、绿色和蓝色发光层的三种磷光体的白色 PhOLED 采用相同的器件结构制造，其最大电流效率和 η 分别为 40.4 cd/A 和 17.8%，显色指数值为 75。
