Since the discovery that it is possible to dope conjugated polymers into high electrical conductivity the research in the field of conjugated polymers has increased a lot. Much of the research activity has been concentrated to the design and fabrication of light emitting devices. The performance of a device is affected by a large number of different parameters, such as the choice of charge injecting metals and what type of polymer is used. In this work we have studied the effect of a low workfunction electrode metal in a device and the effect of using a polymer blend as active material. We have also studied the electronic and chemical structure of some polymers designed for electron transport.