New Approach to Color Variable Light-Emitting Devices Based on ConjugatedPolymers

摘要

Recently there have been reports on color variable light emitting devices. Herewe present a new approach to such devices based on conjugated polymers. The device consists of a blend of pyridine-phenylene and thiophene-phenylene based copolymers sandwiched between two redox polymers: emeraldine base form of polyaniline and sulfonated polyaniline (SPAN). ITO and Al are used as electrodes. The devices work under either polarity of driving voltage with different colors of light being emitted from different locations, red from emitting polymer/SPAN interface under forward bias and green from bulk of the emitting polymers under reverse bias. Electroluminescence of the devices peak at 550 nm with a shoulder at 585 nm under reverse bias while they show a single peak at 665 nm under forward bias. The relative fast time response allows the rapid switch of colors and AC operation.