| 초록 |
Vinyl addition copolymerization of norbornene monomers using a Pd(II) catalyst in combination with 1-octene chain transfer agent efficiently produces well-defined soluble polynorbornene copolymers bearing side-chain (C^N)2Ir(O^O) emitters and 9,9'-(1,3-phenylene)bis-9H-carbazole (mCP) or 9,9'-(1,1'-biphenyl)-4,4'-diylbis-9H-carbazole (CBP) host moieties. The catalytic system provides high-molecular-weight copolymers with a controlled incorporation of monomers. Among the solution-processed devices fabricated based on a single emissive layer comprising the blue-, green-, and red-phosphorescent copolymers (PBn, PGn, and PRn, n = 1–4) with various concentrations of emitters (1.7–13.9 mol%-Ir), the devices based on PB4 (10.5 mol%-Ir), PG2 (5.5 mol%-Ir), and PR4 (13.9 mol%-Ir) display the best performances with maximum power efficiencies of 12.9, 25.6, and 3.3 lm/W and maximum external quantum efficiencies of 8.8, 13.3, and 5.1%, respectively, for each color. |
