Carbazole based polymers as hosts for blue iridium emitters: synthesis, photophysics and high efficiency PLEDs

Stanislovaityte, E.; Simokaitiene, J.; Raisys, S.; Al-Attar, H.; Grazulevicius, J.V.; Monkman, A.P.; Jankus, V.

Abstract

This article reports the synthesis of new carbazole based polymers and their application as hosts in sky-blue polymer light emitting devices (PLEDs) with a solution-processed emitting layer doped with a cyclometalated Ir(III) complex. We systematically investigate their effect on the PLED performance. A current efficiency of 19.7 cd A(-1) and a brightness of 1850 cd m(-2) were achieved with these polymers. The roll-off in electrophosphorescent quantum efficiency in PLEDs was shown to arise mainly from triplet-triplet annihilation between dopants in the hosts with tert-butyl groups. It has been shown that in the devices with hosts without tert-butyl groups the efficiency roll-off is additionally affected by electric field quenching. In these carbazole based polymers, triplet dimers are formed and tert-butyl groups do not limit the intermolecular interactions to prevent triplet dimer formation, nevertheless tert-butyl groups reduce charge transport.

Citation

Stanislovaityte, E., Simokaitiene, J., Raisys, S., Al-Attar, H., Grazulevicius, J., Monkman, A., & Jankus, V. (2013). Carbazole based polymers as hosts for blue iridium emitters: synthesis, photophysics and high efficiency PLEDs. Journal of Materials Chemistry C Materials for optical and electronic devices, 1(48), 8209-8221

• Journal Article Type: Article
• Publication Date: 2013
• Deposit Date: Jan 18, 2017
• Journal: Journal of Materials Chemistry C Materials for optical and electronic devices
• Print ISSN: 2050-7526
• Publisher: Royal Society of Chemistry
• Volume: 1
• Issue: 48
• Pages: 8209-8221
• Publisher URL: <Go to ISI>://WOS:000327546300030