Highly efficient green light-emitting diodes with aluminium cathode

A novel silyl-substituted solvent processible poly(1,4-phenylenevinylene) (PPV) derivative, poly(2-dimethyloctylsily 1-1, 4phenylenevinylene) (DMOS-PPV) and copolymers of DMOS-PPV and poly(2-methoxy-5-ethylhexyloxy-1,4-phenylenevinylene) (MEH-PPV) have been synthesized by the dehydrohalogenation route, and the light-emitting properties of these polymers have been studied. Electroluminescent devices were fabricated with these polymers as emitting layers, and ITO and Al as anode and cathode, respectively. A single layer device using DMOS-PPV as the emissive layer showed 0.2 % internal quantum efficiency. Single layer devices using the copolymers showed internal quantum efficiencies between 0.1 – 0.02 % depending on the copolymer compositions.