Construction of High Tg Bipolar Host Materials with Balanced Electron鈥揌ole Mobility Based on 1,2,4-Thiadiazole for Phosphorescent Organic Light-Emitting Diodes

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• 作者：Jiangjiang Jin ; Wenzhi Zhang ; Bo Wang ; Guanyuan Mu ; Peng Xu ; Lei Wang ; Hong Huang ; Jiangshan Chen ; Dongge Ma
• 刊名：Chemistry of Materials
• 出版年：2014
• 出版时间：April 8, 2014
• 年：2014
• 卷：26
• 期：7
• 页码：2388-2395
• 全文大小：574K
• 年卷期：v.26,no.7(April 8, 2014)
• ISSN：1520-5002

文摘

A novel electron-transporting moiety, 1,2,4-thiadiazole, was first introduced to construct bipolar host molecules for phosphorescent organic light-emitting diodes (PhOLEDs). By incorporating 1,2,4-thiadiazole with typical hole-transporting carbazole moieties, a series of thiadiazole/carbazole hybrids, o-CzTHZ, m-CzTHZ, and p-CzTHZ, were synthesized. All the hybrids exhibit very high glass transition temperatures (T_g 鈮?167 掳C) and show good thermal and morphological stability in films. Moreover, these host materials possess good bipolar charge transporting properties; electron and hole mobilities of these bipolar thiadiazole/carbazole hybrids can be tuned by simply adjusting the linkage modes between thiadiazole and carbazole moieties. The maximum external quantum efficiencies (畏_EQE,聽max) in the green PhOLEDs with o-CzTHZ, m-CzTHZ, and p-CzTHZ as the hosts reached 26.1%, 24.0%, and 22.9%, respectively, and their EQE were still over 20% even at the high luminance of 10,000 cd/m². This study demonstrates that 1,2,4-thiadiazole should be an excellent electron-transporting unit for bipolar phosphorescent hosts.