Issue 16, 2013

Highly efficient phosphorescent OLEDs with host-independent and concentration-insensitive properties based on a bipolar iridium complex

Abstract

A bipolar iridium complex, (ppy)2Ir(dipig), based on the ancillary ligand N,N′-diisopropyl-diisopropyl-guanidinate (dipig) with well-known cyclometalated (C^N) ligand ortho-(2-pyridyl)phenyl (ppy), is applicable in phosphorescent organic light-emitting diodes (PHOLEDs) as an efficient emitter, using easily available host materials and a simple device fabrication process. The corresponding PHOLEDs are dominated by an efficient direct-exciton-formation mechanism and show very high EL efficiency together with gratifying host- and doping-concentration-independent features. EL efficiency values of more than 93 lm W−1 for power efficiency (ηp) and 24% for external quantum efficiency (ηext) accompanied by little efficiency roll-off at high luminance are achieved in the (ppy)2Ir(dipig)-based devices by adopting the common materials 4,4′-bis(N-(1-naphthyl)-N-phenylamino)biphenyl (NPB) and 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene (TPBI) as the host, with rather random concentration ranges of 8–15 wt% and 15–30 wt%, respectively. To the best of our knowledge, these values are the highest efficiencies ever reported for yellow PHOLEDs, and are even comparable with the highest levels for PHOLEDs in the scientific literature. Moreover, the ηp and ηext values of the non-doped device can reach 70 lm W−1 and 18% respectively. They are almost two times higher than those of the most efficient reported PHOLEDs based on a neat emitting layer (EML).

Graphical abstract: Highly efficient phosphorescent OLEDs with host-independent and concentration-insensitive properties based on a bipolar iridium complex

Supplementary files

Article information

Article type
Paper
Submitted
26 Oct 2012
Accepted
26 Feb 2013
First published
27 Feb 2013

J. Mater. Chem. C, 2013,1, 2920-2926

Highly efficient phosphorescent OLEDs with host-independent and concentration-insensitive properties based on a bipolar iridium complex

T. Peng, G. Li, K. Ye, C. Wang, S. Zhao, Y. Liu, Z. Hou and Y. Wang, J. Mater. Chem. C, 2013, 1, 2920 DOI: 10.1039/C3TC00500C

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements