Synthesis and electroluminescent properties of fluorene-based copolymers

A series of novel soluble conjugated copolymers derived from 9,9-dioctylfluorene (DOF) with 4,7-dithien-2-yl-2,1, 3-benzothiadiazole (DBT)) were synthesized by palladium-catalyzed Suzuki coupling reaction. The copolymers of DOF-co-DBT emit saturated red emission which is red-shifted with the increasing DBT contents. Highest external electroluminescence (EL) quantum efficiency of the devices based on flee copolymers exceeds 1.4% for copolymer with 15% DBT content. The results indicate that the DOF-co-DBT copolymers are promising candidate for full-colour polymer flat panel display.