Utilizing Electroplex Emission to Achieve External Quantum Efficiency up to 18.1% in Nondoped Blue OLED
Xuejun Zhan,
Zhongbin Wu,
Yanbin Gong,
Jin Tu,
Yujun Xie,
Qian Peng,
Dongge Ma,
Qianqian Li,
Zhen Li
Affiliations
Xuejun Zhan
Department of Chemistry, Sauvage Center for Molecular Sciences, Wuhan University, Wuhan 430072, China
Zhongbin Wu
Changchun Institute of Applied Chemistry, The Chinese Academy of Sciences, Changchun 130022, China
Yanbin Gong
Department of Chemistry, Sauvage Center for Molecular Sciences, Wuhan University, Wuhan 430072, China
Jin Tu
Department of Chemistry, Sauvage Center for Molecular Sciences, Wuhan University, Wuhan 430072, China
Yujun Xie
Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, China
Qian Peng
Institute of Chemistry, The Chinese Academy of Sciences, Beijing 100190, China
Dongge Ma
State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China
Qianqian Li
Department of Chemistry, Sauvage Center for Molecular Sciences, Wuhan University, Wuhan 430072, China
Zhen Li
Department of Chemistry, Sauvage Center for Molecular Sciences, Wuhan University, Wuhan 430072, China; Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, China
For the first time, electroplex emission is utilized to enhance the performance of nondoped blue organic light-emitting diodes (OLEDs). By decorating the twisted blue-emitting platform and adjusting the electronic structure, three molecules of 3Cz-Ph-CN, 3Cz-mPh-CN, and 3Ph-Cz-CN with a donor-acceptor structure are synthesized and investigated. When external voltage is applied, electroplex emission, which contributes to the emission performance of OLED, can be realized at the interface between the emitting layer and the electron-transporting layer. Accordingly, high external quantum efficiency of 18.1% can be achieved, while the emission wavelength of the device can be controlled in the blue region. Our results provide the possibility to enhance the performance of OLED through electroplex emission, in addition to the generally investigated thermally activated delayed fluorescence (TADF). Excitedly, when 3Ph-Cz-CN is used as host material in orange-emitting phosphorous OLEDs (PO-01 as the dopant), unprecedented high external quantum efficiency of 27.4% can also be achieved.
