Cyclometalated Ir(III) Complexes for High-Efficiency Solution-Processable Blue PhOLEDs

Kozhevnikov, Valery N.; Zheng, Yonghao; Clough, Matthew; Al-Attar, Hameed A.; Griffiths, Gareth C.; Abdullah, Khalid; Raisys, Steponas; Jankus, Vygintas; Bryce, Martin R.; Monkman, Andrew P.

doi:10.1021/cm4010773

Cyclometalated Ir(III) Complexes for High-Efficiency Solution-Processable Blue PhOLEDs

Kozhevnikov, Valery N.; Zheng, Yonghao; Clough, Matthew; Al-Attar, Hameed A.; Griffiths, Gareth C.; Abdullah, Khalid; Raisys, Steponas; Jankus, Vygintas; Bryce, Martin R.; Monkman, Andrew P.

Authors

Valery N. Kozhevnikov

Yonghao Zheng

Matthew Clough

Hameed A. Al-Attar

Gareth C. Griffiths

Khalid Abdullah

Steponas Raisys

Vygintas Jankus

Professor Martin Bryce m.r.bryce@durham.ac.uk
Professor

Andrew P. Monkman

Abstract

This article reports the systematic functionalization of FIrpic (1) with solubilizing alkyl groups (complexes 2–4) or mesityl groups (complexes 5 and 6). Complex 5 is shown to offer significant advantages over FIrpic (1) in terms of performance of sky-blue polymer-based phosphorescent organic light-emitting diodes (PhOLEDs) with a solution-processed emitting layer (λmaxEL 477 nm for 5). Devices with 5 doped into poly(vinylcarbazole) (PVK):OXD-7 gave a maximum luminous efficiency of 19.1 cd A–1 at a brightness of 5455 cd m2 with EQE 8.7%. Optimized multilayer devices with additional TPBi and LiF layers gave 23.7 cd A–1 and EQE 10.4%. These data compare favorably with leading literature values for sky-blue polymer-based PhOLEDs. The enhanced performance of 5 is ascribed to three main reasons: (i) reduced concentration quenching of 5; (ii) the higher radiative yield of 5; and (iii) improved solubility of 5 in organic solvents. Complex 5 should find widespread use as a soluble blue phosphor for displays and lighting applications using solution processing techniques.

Citation

Kozhevnikov, V. N., Zheng, Y., Clough, M., Al-Attar, H. A., Griffiths, G. C., Abdullah, K., …Monkman, A. P. (2013). Cyclometalated Ir(III) Complexes for High-Efficiency Solution-Processable Blue PhOLEDs. Chemistry of Materials, 25(11), 2352-2358. https://doi.org/10.1021/cm4010773

Journal Article Type	Article
Publication Date	Jun 11, 2013
Deposit Date	Nov 24, 2014
Publicly Available Date	Nov 26, 2014
Journal	Chemistry of Materials
Print ISSN	0897-4756
Electronic ISSN	1520-5002
Publisher	American Chemical Society
Peer Reviewed	Peer Reviewed
Volume	25
Issue	11
Pages	2352-2358
DOI	https://doi.org/10.1021/cm4010773
Keywords	Iridium complex, phosphorescence, Electroluminescence, Blue emission, OLED.

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Copyright Statement
This document is the Accepted Manuscript version of a Published Work that appeared in final form in Chemistry of Materials, copyright © 2013 American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://dx.doi.org/10.1021/cm4010773.