Facilitating triplet energy-transfer in polymetallayne-based phosphorescent polymers with iridium(III) units and the great potential in achieving high electroluminescent performances

A series orange phosphorescent copolymers with platinum(II) polymetallayne-based backbone have been successfully prepared through Sonogashira cross-coupling among bicarbazole moieties, 2-(naphthalen-2-yl)pyridine-based Ir-III phosphorescent units, and trans-[PtCl2(PBu3)(2)]. The photophysical investigations have indicated highly efficient energy-transfer from both the singlet and high energy triplet states from the polymetallayne segments to the phosphorescent units in the copolymer backbone due to the proper energy-level matching fulfilled by the 2-(naphthalen-2-yl) pyridine-type ligands in the Ir-III phosphorescent units. Benefiting from these advantages, the phosphorescent polymers can furnish solution-processed phosphorescent OLEDs (PHOLEDs) with high EL efficiencies with current efficiency (eta(L)) of 8.35 cd A(-1), external quantum efficiency (eta(ext)) of 3.79% and power efficiency (eta(P)) of 2.25 lm W-1, representing the very decent electroluminescent performances ever achieved by the orange phosphorescent copolymers. This work herein might not only provides a further study about the novel phosphorescent copolymers with platinum(II) polymetallaynes as backbone, but also provide valuable information for the design and synthesis of highly efficient phosphorescent copolymers. (C) 2015 Elsevier B.V. All rights reserved.