High brightness deep blue/violet fluorescent polymer light-emitting diodes (PLEDs)

Cook, Javan H.; Santos, José; Al-Attar, Hameed A.; Bryce, Martin R.; Monkman, Andrew P.

Abstract

Two new deep blue/violet emitting alternating co-polymers, comprising readily-available carbazole (C) and fluorene (F) monomer units, have been synthesised and shown to produce extremely bright solution-processed polymer light-emitting diodes (PLEDs) with the structure ITO/PEDOT:PSS/polymer/TPBi/LiF/Al. The para-conjugated polymer, CF1, gave PLED devices with external quantum efficiency (EQE) values of ηext,max 1.4%, Lmax of 565 cd m−2 with CIEx,y (0.16, 0.07). The EQE was raised to ηext,max 2.1%, after the addition of a TAPC hole injection layer. For the isomeric meta-conjugated polymer, CF2, values of ηext,max 0.35%, Lmax of 16 cd m−2 with CIEx,y (0.18, 0.12) were obtained. The λELmax was 409 nm for both the CF1 and CF2 devices. The CF1 devices also possess low turn-on and low operating voltages for devices of such high brightness. Moreover, the CF1 emission is very stable from 10 cd m−2 up to peak brightness, with only a negligible shift in CIE coordinates. The combination of a simple co-polymer structure synthesised using readily-available monomer units, and high brightness and good colour stability from a simple device architecture, makes CF1 suitable for a wide range of applications requiring deep blue/violet emission.

Citation

Cook, J. H., Santos, J., Al-Attar, H. A., Bryce, M. R., & Monkman, A. P. (2015). High brightness deep blue/violet fluorescent polymer light-emitting diodes (PLEDs). Journal of Materials Chemistry C Materials for optical and electronic devices, 3(37), 9664-9669. https://doi.org/10.1039/c5tc02162f

• Journal Article Type: Article
• Acceptance Date: Aug 25, 2015
• Publication Date: Oct 7, 2015
• Deposit Date: Oct 7, 2015
• Publicly Available Date: Sep 2, 2016
• Journal: Journal of Materials Chemistry C Materials for optical and electronic devices
• Print ISSN: 2050-7526
• Electronic ISSN: 2050-7534
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Volume: 3
• Issue: 37
• Pages: 9664-9669
• DOI: https://doi.org/10.1039/c5tc02162f
• Public URL: https://durham-repository.worktribe.com/output/1430141