Norbornene-Based Copolymers with Iridium Complexes and Bis(carbazolyl)fluorene Groups in Their Side-Chains and Their Use in Light-Emitting Diodes

Abstract

Solution-processable copolymers with pendant phosphorescent iridium complexes and 2,7-di(carbazol-9-yl)fluorene-type host moieties were synthesized using ruthenium-catalyzed ring-opening metathesis polymerization. Low polydispersity indices and molecular weights around 20 000 Da were obtained for all copolymers. As a result of the living character of the polymerization of the monomer containing the host moiety, a high degree of control over the molecular weights of all copolymers can be obtained. The photo-and electroluminescence properties of the copolymers were investigated. All copolymers retained the photo-and electrophysical properties of the corresponding nonpolymeric iridium complexes. Furthermore, as a proof of principle for the potential use of these materials, organic light-emitting devices were fabricated using the orange-emitting copolymer. A maximum external quantum efficiency of 1.9% at 100 cd/m 2 and a turn-on voltage of 3.7 V were obtained with photoluminescence quantum yield of 0.10 demonstrating the potential of these copolymers as emissive materials for display and lighting applications.

Recent Developments in the Application of Phosphorescent Iridium(III) Complex Systems

“…Weck and co-workers used the ring-opening metathesis polymerization (ROMP) of functionalized exo-norbornene [134,136] or cyclooctene monomers [135] to synthesize homo-and copolymers equipped with Ir III emitters. A first proof of the feasibility was gained by polymerizing norbornenes bearing tris-cyclometallated (facial and meridional) complexes as well as charged bis-cyclometallated iridium(III) bipyridine complexes and by performing copolymerizations with alkyl-functionalized norbornene.…”

“…[135] Further on, norbornenes bearing various heteroleptic tris-cyclometallated Ir III complexes were copolymerized with a (bis-carbazole-fluorene)-norbornene derivative. [136,137] Testing several materials in a multilayer device assembly, a maximum efficiency of 4.9% (at 100 cd m 2 ) could be realized. [137] Ulbricht and co-workers [138] and Rehmann et al [139] reported the synthesis of oxetane-functionalized bis-cyclometallated iridium(III) acetoacetate complexes and the optimization of multilayer OLEDs employing these emitters, which were covalently incorporated into a crosslinked matrix.…”

Metal–Ligand‐Containing Polymers: Terpyridine as the Supramolecular Unit

“…According to the Equations shown in Figure 3, [19][20][21]23,24,[28][29][30] has received some attention in polymeric side chains. [31][32][33] Despite the limited binding constant data available for the environments in which supramolecular polymer chemistry studies have been conducted, a variety of interesting materials have been reported. The focus below shifts from fundamental binding constant studies to a discussion of synthetic methods used to generate macromolecules inspired by Figure 1 and then a brief highlight of various materials generated from these novel macromolecules.…”

Polymers that Contain Ligated Metals in their Side Chain: Building a Foundation for Functional Materials in Opto‐Electronic Applications with an Emphasis on Lanthanide Ions

“…[25] More recently the electroluminescence of poly(norbornene) based devices was reported. [39,40] With several recent reviews available, [6,41] and the fact that a detailed review of this area is well beyond the scope of this Feature Article, further discussion on these important transition metal-containing polymers will be deferred so that attention can be given to lanthanide-based materials.…”