Polarity- and voltage-controlled color-variable light-emitting devices based on conjugated polymers

There is increased interest in developing multilayer color-variable light-emitting devices. So far, the multilayer color-variable light-emitting devices mainly have focused on polarity-controlled two-color light-emitting devices. We report here the fabrication and study of voltage- and polarity-controlled multilayer multicolor light-emitting devices based on pyridine-containing conjugated polymers and derivatives of polyacetylene. The devices emit red light under forward bias and multiple colors of light (from orange-red to green) under reverse bias. The colors under reverse bias are controlled by the magnitude of the applied voltages.