Peripheral carbazole or cyano substitutents in poly (aryl ether) based bipolar polymeric hosts: Increase the hole or electron injection properties for blue phosphorescent polymer light emitting diodes

A series of poly (aryl ether) based bipolar polymer hosts, PCzOPOC8, PCzOPOCz, and PCzOPOCN with a peripheral carbazole or cyano unit which joins the main chain by a nonconjugated linker of a hexyl group, were synthesized and characterized. They depicted high triplet level (ET) (>2.80 eV), which was probably attributed to oxygen‐interrupted nonconjugated main chains of polymers as well as carbazole and phosphine oxide groups with high ET. While doped with a 10 wt% typical blue phosphor {iridium(III)[bis(4,6‐difluoro phenyl)pyridinato‐N, C2]picolinate, FIrpic)}, compared with those of nonsubstituted PCzOPOC8 and peripheral cyano‐substituted PCzOPOCN, PCzOPOCz with carbazole moiety gave better performances due to balance of carrier flux from carbazole moiety with good hole transport ability.