Blue-light emitting diodes and flat display based on poly (p-phenylenevinylene) copolymers

Copolymers containing alternating flexible aliphatic blocks and rigid poly (p-phenylenevinylene) (PPV) blocks were synthesized and characterized. It was found that the fluorescent intensity increases with increasing length of the flexible blocks. Bright blue-light emitting diodes were fabricated using PPV copolymers as electroluminescent layers. The devices show 190 cd/m² light-emitting brightness at 460 nm and 15 V turn-on voltage. The effects of oxadiawle derivative PBD and tris(8-hydroxyquinoline) aluminum Alq₃ electron-transporting layers on the luminance and stability of the devices are discussed. Project supported by the National Natural Science Foundation of China, PCLCC, the State Comission of Science and Technology of China (863-715-002-0130) and the Chinese Acadeny of Sciences (KJ951-A1-501-01)