Light-emitting devices based on pyridine-containing conjugated polymers

We report the fabrication of light-emitting devices based on several pyridine-containing conjugated polymers and copolymers in various device configurations. The high electron affinity of pyridine based polymers enables the use of relatively stable metals such as Al or even ITO as electron injecting contacts. Taking advantages of the better electron transport properties of the pyridine-containing polymers, we fabricate bilayer devices utilizing poly(9-vinyl carbazole) (PVK) as hole transporting/electron blocking polymer, which improves the device efficiency and brightness significantly due to the charge confinement and exciplex emission at the PVK/emitting polymer interface. The incorporation of conducting polyaniline network electrode to PVK reduces the device turn on voltage significantly while maintaining the high efficiency. The control of the aggregate formation in the polymer films by blending with insulating host polymers opens up the possibility of making voltage-controlled multi-color light-emitting devices.