Optimizing the conjugation between N,N¡ä-dicarbazolyl-3,5-benzene and triphenylphosphine oxide as bipolar hybrids for highly efficient blue and single emissive layer white phosphorescent OLEDs

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• 作者：Hong Huang ; Xiao Yang ; Yixing Wang ; Biao Pan ; Lei Wang ; Jiangshan Chen ; Dongge Ma ; Chuluo Yang
• 关键词：Bipolar host ; N ; N&prime ; -Dicarbazolyl-3 ; 5-benzene ; Blue phosphorescent organic light-emitting device ; The single emission layer
• 刊名：Organic Electronics
• 出版年：2013
• 出版时间：October, 2013
• 年：2013
• 卷：14
• 期：10
• 页码：2573-2581
• 全文大小：1012 K

文摘

Two bipolar host materials, mCPpPO and mCPmPO have been synthesized by Ni(II)/Zn-catalyzed cross-coupling of diphenylphosphine oxide and corresponding aryl bromide. The photophysical properties, HOMO/LUMO orbital distribution and triplet levels of these host materials are investigated and optimized by tuning the linking modes between electron acceptor triphenylphosphine oxide and electron donor N,N¡ä-dicarbazolyl-3,5-benzene (mCP). When mCP is linked to the meta-position of benzene of triphenylphosphine oxide, the hybrid (mCPmPO) shows much higher steric hinderance than the para-position linked analogue (mCPpPO) so that it possesses a higher triplet energy. Equipped with the bipolar transport properties, mCPmPO-based blue PhOLED doped FIrpic shows a maximum current efficiency (¦Ç_c,max) of 40.0 cd/A, a maximum power efficiency (¦Ç_p,max) of 39.7 lm/W, corresponding the maximum external quantum efficiency (¦Ç_EQE,max) of 20.3 % , and the current efficiency still maintain to 34.8 cd/A even at 1000 cd/m². Based on the optimized triplet energy level, the single emission layer white PhOLED hosted by mCPmPO shows ¦Ç_c,max, ¦Ç_p,max and ¦Ç_EQE,max of 46.9 cd/A, 39.7 lm/W and 17.6 % , respectively.