초록 |
The soluble polynorbornene with 4,4'-bis(9-carbazolyl)-biphenyl (CBP) side groups was efficiently produced by the Pd(II)-catalyzed vinyl addition polymerization of norbornene monomer in combination with 1-octene chain transfer agent. The polymer shows high thermal stability (Td5>400 °C) as well as high glass transition temperature (Tg>360 °C). When being incorporated into the emissive layer as the host doped with various concentration of fac-Ir(ppy)3 (1 ~ 6 wt%) through solution process, all the devices emitted nearly identical green phosphorescence with an emission maximum at 512 nm. Among the devices based on the title polymer host, particularly, 2 wt%-doped device displayed the best performance, which is much better than that of PVK-based device and moreover is comparable to that of the identical device structure based on the molecular CBP processed by vacuum deposition technique. Details of synthesis, characterization, and host properties of the polymer will be discussed. |