Recent advances in luminescent dinuclear iridium(III) complexes and their application in organic electroluminescent devices

In contrast to mononuclear iridium(III) complexes, dinuclear iridium(III) complexes have been less well studied, especially as dopants in phosphorescent organic light-emitting devices (PhOLEDs). This is largely a consequence of the established view that dinuclear iridium(III) complexes are poorly emissive and give unsatisfactory device performance. However, this is not always the case. In this review, recent advances in dinuclear iridium(III) complexes and their applications in OLEDs are discussed. Systems with bridges comprising bis(mu-Cl), bis(ji-NCO), N boolean AND N, N boolean AND O and C boolean AND N structures are included. The relationships between chemical structures and luminescent properties are presented. Additionally, recent reports of good electroluminescence (EL) performance of dinuclear iridium(III) emitters demonstrate that rationally designed diiridium complexes present a feasible alternative to typical monoiridium systems in optoelectronic applications, with the bridging ligands providing additional structural versatility. (C) 2017 Elsevier Ltd. All rights reserved.