Issue 31, 2012

The use of a polarity matching and high-energy exciton generating host in fabricating efficient purplish-blue OLEDs from a sky-blue emitter

Abstract

We reveal in this communication a new finding regarding the use of a sky-blue emitter to generate purplish-blue emission from organic light emitting diodes (OLEDs) with a polarity matching and high-energy exciton generating host. The resulting device exhibits CIExy coordinates of (0.155, 0.063) and a 3.5% external quantum efficiency, with a 1.2 lm W−1 power efficiency at 100 cd m−2 as a sky-blue emitter, 1-((9,9-diethyl-9H-fluoren-2-yl)ethynyl)pyrene with CIExy of (0.190, 0.241) is doped into a host of 4,4′-bis(9-carbazolyl)-biphenyl, for example. The resulting purplish-blue emission enables a greater than 100% color saturation. The extraordinarily marked blue-shift may result from a low doping concentration to prevent bathochromic shift due to emitter segregation, a polarity matching host to further disperse the emitter, and an efficient host and guest energy level pairing that enables excitons to be generated on the host to trigger short wavelength emission. Furthermore, the host is capable of generating excitons with higher energy to facilitate the triggering of emission with a shorter wavelength. The high efficiency may be attributed to the low doping concentration preventing efficiency roll-off caused by concentration-quenching, the excitons generated on the host facilitating the occurrence of the effective host-to-guest energy transfer, and the employed host possessing an effective host-to-guest energy transfer effect. Notably, the new approach also works for other light-blue emitters in yielding a highly desirable deep-blue light, provided their molecular structure is free of steric hindrance.

Graphical abstract: The use of a polarity matching and high-energy exciton generating host in fabricating efficient purplish-blue OLEDs from a sky-blue emitter

Article information

Article type
Communication
Submitted
09 Apr 2012
Accepted
21 Jun 2012
First published
22 Jun 2012

J. Mater. Chem., 2012,22, 15500-15506

The use of a polarity matching and high-energy exciton generating host in fabricating efficient purplish-blue OLEDs from a sky-blue emitter

J. Jou, Y. Chen, J. Tseng, R. Wu, J. Shyue, K. R. Justin Thomas, N. Kapoor, C. Chen, Y. Lin, P. Wang, H. Hung, J. Li and S. Chen, J. Mater. Chem., 2012, 22, 15500 DOI: 10.1039/C2JM32216A

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.

Spotlight

Advertisements