2012 年 66 巻 10 号 p. J370-J376
This study reports on the synthesis of red phosphorescent, solution processable chain-end functional, mid-chain- and three-arm star polymers from a functionalized styryl monomer host and a RAFT agent containing a tris-cyclometalated Ir(III) complex phosphorescent group (dopant). The polymerization was carried out in toluene at 120°C, and the resulting polymers showed a narrow molecular weight distribution (Ð<1.3) and contained approximately 6-11 mol% of the Ir(piq)3 complex. All polymers showed good solubility in non-polar organic solvents and exhibited red emission. Of these polymers, the three-arm star polymer showed better energy transfer (in film) compared to the midchain functional and end chain functional polymers. No significant difference in optical properties and energy levels was found for the end functional vs the mid-chain and three-arm star polymers. Preliminary device evaluation of the end functional Ir(piq)3 poly(host) showed a current efficiency of 0.4 cd/A at 10 mA/cm2 and a voltage of 10.5 V with color CIE 1931 coordinate (0.68, 0.31).
