Novel light-emitting electrophosphorescent copolymers based on carbazole with an Ir complex on the backbone.

Autor: Hongyu Zhen, Jie Luo, Wei Yang, Qiliang Chen, Lei Ying, Zou Jianhua, Hongbin Wu, Yong Cao
Zdroj: Journal of Materials Chemistry; Jul2007, Vol. 17 Issue 27, p2824-2831, 8p
Abstrakt: Novel light-emitting phosphorescent polymers based on 3,6-carbazole with an iridium complex on the backbone were synthesized by Suzuki polycondensation of A-A and B-B type monomers. Three difluoro-substituted phenylpyridine iridium complexes with different ancillary ligands (FIrptz, FIrpic and FIrtmd) were introduced into the poly(3,6-carbazole) (PCz) backbone, causing distinct differences in the photo- and electroluminescence properties. The PL efficiency of PCz-FIrtmd5 is as high as 62% compared with the value of 9% of the fluorene-alt-carbazole-based copolymer (PFCz-FIrtmd5), which indicated that the 3,6-carbazole unit was suitable to serve as the host for a green electrophosphorescent polymer. The ancillary ligand of bicycloiridium complexes also affects the device performance based on chelating copolymers. The best device performances were obtained from copolymer PCz-FIrtmd5 with the maximal luminous efficiency of 4.4 cd A−1 and a luminance of 453 mA cm−2 at a current density of 10.3 mA cm−2 with the configuration: ITO/PEDOT/polymer + PBD(30 wt%)/Ba/Al. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index