LIGHT-EMITTING DEVICES BASED ON PYRIDINE-CONTAINING CONJUGATED POLYMERS

We report the fabrication of light-emitting devices based on several p yridine-containing conjugated polymers and copolymers in various devic e configurations. The high electron affinity of pyridine based polymer s enables the use of relatively stable metals such as Al or even ITO a s electron injecting contacts. Taking advantages of the better electro n transport properties of the pyridine-containing polymers, we fabrica te bilayer devices utilizing poly(9-vinyl carbazole) (PVK) as hole tra nsporting/electron blocking polymer, which improves the device efficie ncy and brightness significantly due to the charge confinement and exc iplex emission at the PVK/emitting polymer interface. The incorporatio n of conducting polyaniline network electrode to PVK reduces the devic e turn on voltage significantly while maintaining the high efficiency. The control of the aggregate formation in the polymer films by blendi ng with insulating host polymers opens up the possibility of making vo ltage-controlled multi-color light-emitting devices.