Voltage tunable multicolor light emitting diodes based on a dye-doped polythiophene derivative

The electroluminescence behavior of polymeric light emitting diodes based on poly[2-(3-thienyl)ethanol-n-butoxy carbonyl-methylurethane] (PURET) as an emitting layer has been studied. The organic layer has been doped with varying concentrations of 4-dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM) dye. On addition of a very small amount of the dye, a voltage tunable multicolor emission with enhanced luminance ∼1000 cd/m2 has been observed. The mechanism of conduction responsible for color tuning has been explored.