High efficiency green phosphorescent organic light-emitting diodes with a low roll-off at high brightness

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• 作者：Jing Wang ; Jun Liu ; Saijun Huang ; Xinkai Wu ; Xindong Shi ; Chaoping Chen ; Zhicheng Ye ; Jiangang Lu ; Yikai Su ; Gufeng He ; Youxuan Zheng
• 关键词：Organic light emitting ; High efficiency ; Low roll-off ; Co-host
• 刊名：Organic Electronics
• 出版年：2013
• 出版时间：November, 2013
• 年：2013
• 卷：14
• 期：11
• 页码：2854-2858
• 全文大小：1188 K

文摘

Highly efficient green phosphorescent organic light-emitting diodes (PHOLEDs) with low efficiency roll-off at high brightness have been demonstrated with a novel iridium complex. The host material 1,3-bis(carbazol-9-yl)benzene (mCP) with high triplet energy is also used as the hole transporting layer to avoid carrier accumulation near the exciton formation interface and reduce exciton quenching. It provides a new approach for easily fabricating PHOLED with high triplet energy emitter. Moreover, the hole blocking layer is extended into the light emitting layer to form a co-host, realizing better control of the carrier balance and broader recombination zone. As a consequence, a maximum external quantum efficiency of 20.8 % and current efficiency of 72.9 cd/A have been achieved, and maintain to 17.4 % and 60.7 cd/A even at 10,000 cd/m², respectively.