Researchers at South China University of Technology, have reported a versatile electron transport/hole blocking material (HBL) Phen-m-PhDPO possessing a deep HOMO level, wide bandgap, high triplet energy and a Tg of 94 °C, through a simple combination of m-diphenylphosphinylphenyl moiety with a 1,10-phenanthroline unit.
According to the researchers - the sky blue fluorescent, green and red phosphorescent OLEDs based on a pin device architecture incorporating a thin Phen-m-PhDPO HBL provided potentially high power efficiencies with promising operational stability.
Of interest is Phen-m-PhDPO which exhibits a considerably low electron mobility of 6.34 × 10−8–1.58 × 10−6 cm2 V−1 s−1 at E = 2–5 × 105 V cm−1, it affords generally enhanced power efficiencies over a common hole blocking layer TPBi (1,3,5-tris(N- phenylbenzimidazolyl)benzene) with a higher electron mobility.
The preliminary finding has shown power efficiency of 41 lm/W @ 1000 cd m-2 and half lifetime t50 of around 40 hours at an initial luminance of ~10,000 cdm-2 for the green phosphorescent OLED.
Figure: South China University of Technology - OLED device
Promising Operational Stability of Potentially High Power Efficiency Organic Light-Emitting Diodes Utilizing a Simple and Versatile Electron-Transport/Hole-Blocking Layer
Wan-Yi Tan | Jian-Hua Zou | Dong-Yu Gao | Jun-Zhe Liu | Ning-Ning Chen | Xu-Hui Zhu | Junbiao Peng | Yong Cao
First published: 21 April 2016 | DOI: 10.1002/aelm.201600101
An electron-transport/hole blocking material Phen-m-PhDPO (3-(m-diphenyl phosphinyl phenyl)-1,10-phenanthroline) is utilized for red, green phosphorescent and blue fluorescent organic light-emitting diodes to show potentially high power efficiencies and operational stability, despite a low electron mobility of 6.34 × 10−8–1.58 × 10−6 cm2 V−1 s−1 at E = 2–5 × 105 V cm−1.