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/m(2) light-emitting brightness at 460 nm and 15 V rum-on voltage. The effects of oxadiazole derivative PBD and tris(8-hydroxyquinoline) aluminum Alq(3) electron-transporting layers on the luminance and stability of the devices are discussed.