Oxadiazole-containing phenylene vinylene ether linkage copolymer as blue-green luminescent and electron transport material in polymer light-emitting diodes

We report studies on a new ether-type poly(phenylene vinylene) (PPV) copolymer containing oxadiazole groups in the conjugated main chain. It can be used as a blue-green electroluminescent material and as an electron transport/hole blocking material in polymer light-emitting diodes using PPV as the emitting material. The bilayer devices with aluminum cathode show a maximum brightness of about 300 cd/m2 at about 21 V and a maximum external quantum efficiency of 0.1%. The quantum efficiency of the bilayer device is enhanced by a factor of 195 in comparison with that of the single layer device of PPV.