Star-Shaped Oligotriarylamines with Planarized Triphenylamine Core: Solution-Processable, High-Tg Hole-Injecting and Hole-Transporting Materials for Organic Light-Emitting Devices

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• 作者：Zuoquan Jiang ; Tengling Ye ; Chuluo Yang ; Dezhi Yang ; Minrong Zhu ; Cheng Zhong ; Jingui Qin ; Dongge Ma
• 刊名：Chemistry of Materials
• 出版年：2011
• 出版时间：February 8, 2011
• 年：2011
• 卷：23
• 期：3
• 页码：771-777
• 全文大小：901K
• 年卷期：v.23,no.3(February 8, 2011)
• ISSN：1520-5002

文摘

Two novel star-shaped oligotriarylamines with planar triphenylamine core and peripheral triarylamine groups, namely FATPA-T and FATPA-Cz, were synthesized by Suzuki cross-coupling reaction. The molecular design imparts the materials with the following features: (i) excellent thermal stabilities with quite high glass transition temperatures (237 掳C for FATPA-T and 272 掳C for FATPA-Cz); (ii) good solution-processability; (iii) good hole mobility, efficient hole injection, and electron-blocking functions. Furthermore, their optoelectronic properties can be modulated by the peripheral triarylamine groups. For example, FATPA-T with triphenylamine peripheries shows the significantly red-shifted absorption and emission, as well as the small band gap as compared to FATPA-Cz with carbazole peripheries. Double-layer Alq₃-emitting OLEDs using FATPA-T or FATPA-Cz as hole-transport layer by spin-coating method were fabricated, and the FATPA-Cz-based devices show greatly improved performance as compared to standard NPB-based device by vacuum-evaporation of NPB. The optimized three-layer Alq₃-emitting OLEDs by using FATPA-Cz and NPB as double hole-transport layers exhibit the maximum current efficiency of 6.83 cd/A, which is the highest for the Alq₃-based green emission under the similar device structures. The advantages of solution-processablity and very high T_g make the star-shaped oligotriarylamines ideal substitutes for conventional arylamines as hole-inject and hole-transport materials.