http://dx.doi.org/10.1002/ejic.201200064">
 

Document Type

Journal Article

Department/Unit

Department of Chemistry

Title

Simple tuning of the optoelectronic properties of IrIII and PtII electrophosphors based on linkage isomer formation with a naphthylthiazolyl moiety

Language

English

Abstract

By tuning the substitution position of a thiazolyl group on the naphthalene system (α or β site), the distinctive electronic structures associated with these functional ligands have a substantial influence on both the photophysical behavior and electroluminescent (EL) performance of the resulting linkage isomers for two series of Ir III and Pt II phosphorescent emitters. The photoluminescence wavelength can be redshifted by ca. 23 nm for the linkage isomers upon replacing the β-substituted thiazolyl-based ligand with its α-substituted counterpart in the homoleptic series of Ir III phosphors. Furthermore, the bathochromic effect can be as much as ca. 42 nm for the heteroleptic Ir III phosphors and ca. 59 nm for the Pt II compounds. Similarly, metallophosphors that bear β-substituted ligands exhibit a different EL performance with respect to that of their linkage isomers with α-substituted ligands. The best EL results associated with the triplet emitters chelated with β-substituted ligands show a maximum brightness (L max) of 22563 cd m -2, an external quantum efficiency (η ext) of 12.88 %, a luminance efficiency (η L) of 30.84 cd A -1, and a power efficiency (η p) of 26.17 lm W -1, whereas the EL performance of their α-counterparts was characterized by a peak L max of 8653 cd m -2, η ext of 6.18 %, η L of 8.55 cd A -1, and η p of 6.54 lm W -1. Owing to its unique electronic structure, the thiazolyl group is a good alternative to the pyridyl moiety to improve the EL performance of the metallophosphor. We have also demonstrated a simple and useful route to tune the functional properties of cyclometalated triplet emitters for EL applications. New thiazole-based phosphorescent emitters with iridium and platinum have been developed and applied in organic light-emitting devices. By simply changing the substitution position of the thiazolyl moiety on the naphthalene ring in each pair of linkage isomers, the optoelectronic and electroluminescent properties of these metallophosphors can be easily tuned. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Keywords

Electrophosphors, Iridium, Luminescence, N, S ligands, Organic light-emitting diodes, Platinum

Publication Date

2012

Source Publication Title

European Journal of Inorganic Chemistry

Volume

2012

Issue

13

Start Page

2278

End Page

2288

Publisher

Wiley-VCH Verlag

ISSN (print)

14341948

ISSN (electronic)

10990682

This document is currently not available here.

Share

COinS