COLOR VARIABLE BIPOLAR AC LIGHT-EMITTING DEVICES BASED ON CONJUGATED POLYMERS/

There is increased interest in developing color variable light emittin g devices. We report here the fabrication of color variable bipolar/ac light-emitting devices based on conjugated polymers. The devices cons ist of blends of pyridine-phenylene and thiophene-phenylene based copo lymers sandwiched between the emeraldine base form and the sulfonated form of polyaniline. ITO and Al are used as electrodes. The devices op erate under either polarity of driving voltage with different colors o f light being emitted, red under forward bias, and green under reverse bias. The relative fast time response allows the rapid switching of c olors and ac operation. (C) 1997 American Institute of Physics.