High efficiency yellow organic light emitting diodes with a balanced carrier injection co-host structure

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Vol. 1; no. 33; pp. 5110 - 5115
• Main Authors: Jou, Jwo-Huei, Yu, Hui-Huan, Lin, You-Xing, Tseng, Jing-Ru, Peng, Shiang-Hau, Jou, Yung-Cheng, Lin, Chun-Hao, Shen, Shih-Ming, Hsieh, Chun-Yu, Wei, Mao-Kuo, Lin, Di-Hong, Wang, Ching-Chiun, Chen, Chien-Chih, Tung, Fu-Ching, Chen, Szu-Hao, Wang, Yi-Shan
• Format: Journal Article
• Language: English
• Published: 01.01.2013
• Subjects: Balancing; Carrier injection; Current efficiency; Devices; Effectiveness; Organic light emitting diodes; Resultants
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/c3tc30818a

We demonstrate herein the design and fabrication of a highly efficient yellow organic light-emitting diode (OLED) with a balanced carrier injection device architecture having a zero electron-injection-barrier host blended with a hole-injection aiding co-host. The resultant yellow OLED showed, at 1000 cd m super(-2) for example, an efficacy of 59 lm W super(-1), current efficiency of 71 cd A super(-1) and external quantum efficiency (EQE) of 23%, with values of 42 lm W super(-1), 47 cd A super(-1) and 15% EQE without a co-host. The co-host effect that resulted in very balanced carrier injection was also valid for other yellow OLED devices and their efficiency improvement was also very marked. With the use of a micro-lens, the device efficiency is further improved to 79 lm W super(-1), 96 cd A super(-1) and 30% EQE.