Synthesis and Light-Emtting Diodes Properties of Two New Fluorene Based Copolymers

Two new conjugated copolymers, PFPh and PFTDP, comprised of alternating 9,9-dioctylfluorene and phthalimide (Ph) or thieno [3, 4-c] pyrrole-4,6-dione (TPD) have been synthesized via Suzuki coupling reaction. Polymeric light-emitting diodes (PLED) were fabricated with an ITO/PEDOT: PSS/PVK/Polymer/BCP/Alq/Ca:Ag configuration. The maximum brightness and maximum current efficiency of PLED are 2600cd/m2and 2.52 cd/A for PFPh, and 2300cd/m2and 1.13 cd/A for PFTDP, respectively, which are significantly improved compared with the reported alternating fluorene-unsubstituted phenylene/thiophene systems.