ABSTRACT

Polyphenylene and its derivatives represent a typical blue-light-emitting poly­ mer, although the exact emission may vary from violet to green depending on substituents. Because the first blue PLED was reported using poly(p-phenylene) as the emissive layer [76,77], a whole series of soluble blue-light-emitting PPPs have been synthesized [15,46,78-81]. The phenylene units can be bridged to form “ladder” -type PPPs, with the aim of obtaining more stable and efficient blue emission [82,83]. Device efficiencies as high as 4% have been achieved using these materials [84].