C60/ N, N'-bis(1-naphthyl)- N, N'-diphenyl-1,1'-biphenyl-4,4'-diamine:MoO3 as the interconnection layer for high efficient tandem blue fluorescent organic light-emitting diodes

Xiaoming Wu; Wentao Bi; Yulin Hua; Jin'e Sun; Zhihui Xiao; Li Wang; Shougen Yin

doi:10.1063/1.4811551

C₆₀/ N, N'-bis(1-naphthyl)- N, N'-diphenyl-1,1'-biphenyl-4,4'-diamine:MoO₃ as the interconnection layer for high efficient tandem blue fluorescent organic light-emitting diodes

Appl Phys Lett. 2013 Jun 17;102(24):243302. doi: 10.1063/1.4811551. Epub 2013 Jun 18.

Authors

Xiaoming Wu¹, Wentao Bi, Yulin Hua, Jin'e Sun, Zhihui Xiao, Li Wang, Shougen Yin

Affiliation

¹ Key Laboratory of Display Materials and Photoelectric Devices, Ministry of Education, School of Materials Science and Engineering, Tianjin University of Technology, Tianjin 300384, China.

Abstract

The high efficient tandem blue fluorescent organic light emitting diodes (OLEDs) with the transparent interconnection layer (ICL) of fullerence (C₆₀)/Molybdenum oxide (MoO₃)-doped N,N'-bis(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine (NPB) were presented. A stack consisting of 0.5 nm of LiF and 1 nm of Ca, which is located from C₆₀ to adjacent electron transporting layer is used as an electron injection layer. The experiment results indicate that the luminance of the tandem device is basically equal to that of the traditional single-unit device, but the current density of the tandem device is much less than that of the single-unit device under a same luminance. The current efficiency and the maximal power efficiency of tandem device with LiF/Ca/C₆₀/NPB:MoO₃/MoO₃-based interconnection layer have been approximately enhanced by 250% and 126%, respectively. In addition, we also analyze that the mechanism of the efficiency enhancement is ascribed to the effective charge separation and transport of the ICL in tandem OLEDs.