Low efficiency roll-off and high color stability pure fluorescent white organic light-emitting diode based exciplex host

Heng Zhang; Ziqi Wang; Long Gao; Bo Zhao; Wenlian Li

doi:10.1039/c7ra11325k

Low efficiency roll-off and high color stability pure fluorescent white organic light-emitting diode based exciplex host

RSC Adv. 2018 Jan 3;8(2):954-959. doi: 10.1039/c7ra11325k. eCollection 2018 Jan 2.

Authors

Heng Zhang^{1

2}, Ziqi Wang^{1

2}, Long Gao^{1

2}, Bo Zhao^{1

2}, Wenlian Li³

Affiliations

¹ Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology Taiyuan 030024 P. R. China.
² Research Center of Advanced Materials Science and Technology, Taiyuan University of Technology Taiyuan 030024 P. R. China zhaobo01@tyut.edu.cn.
³ State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics, and Physics, Chinese Academy of Sciences Changchun 130033 P. R. China.

Abstract

Pure fluorescent WOLEDs with low efficiency roll-off and high color stability were realized by employing an exciplex host. Due to incomplete energy transfer from the blue exciplex host of mCP : PO-T2T to the orange fluorescent dopant of rubrene, the WOLEDs showed a maximum current efficiency, power efficiency and EQE of 14.2 cd A^-1, 12.8 lm W^-1 and 4.90%, respectively. To our surprise, a rather small roll-off ratio of 8.2% from the maximum EQE to the EQE at 1000 cd m^-2 and stable white light-emitting spectra with CIE coordinates of (0.384 ± 0.001, 0.439 ± 0.002) from 4 V to 8 V were obtained simultaneously. The bipolarity and triplet exciton up-conversion of the exciplex host played key roles in delivering excellent performance. More detailed discussions are also provided.