EQE Climbing Over 6% at High Brightness of 14350 cd/m2 in Deep-Blue OLEDs Based on Hybridized Local and Charge-Transfer Fluorescence

作者：Zhao, Juewen; Liu, Bin; Wang, Zhongyi; Tong, Qingxiao^*; Du, Xiaoyang; Zheng, Caijun; Lin, Hui; Tao, Silu^*; Zhang, Xiaohong^*

来源：ACS Applied Materials & Interfaces, 2018, 10(11): 9629-9637.

DOI：10.1021/acsami.7b19646

• indolizine
• conjugated system
• deep blue
• OLEDs
• efficiency roll-off

Three deep-blue emitters PPi-Pid, PPi-Xid, and PPi-Mid based on a novel conjugated system phenantroimidazole-pi-indolizine have been designed and synthesized. Here, indolizine with appropriate pi-conjugation length was used as the acceptor profited from its high-photoluminescence quantum yield and good electron-withdrawing ability. Fluorescent organic light emitting diodes (OLEDs) based on PPi-Pid, PPi-Xid, and PPi-Mid achieved deep-blue emissions with the Commission Internationale de L'Eclairage coordinates of (0.151, 0.076), (0.155, 0.052), and (0.153, 0.052); high brightness of 14350, 4377, and 4002 cd/m(2); and high external quantum efficiencies (EQEs) of 6.01, 3.90, and 4.28%, respectively. Moreover, it is noticeable that all of the devices exhibited efficiencies increasing with brightness. In particular, the PPi-Pid-based device exhibited high EQE over 6% at a high brightness of 14350 cd/m(2). Such high brightness along with high EQE is very rare whether in deep-blue fluorescent or thermally activated delayed fluorescent OLEDs.

• 出版日期2018-3-21
• 单位电子科技大学; 苏州大学; 汕头大学