Since the discovery of conducting polymers three decades ago the field of organic electronics has evolved rapidly. Organic light emitting diodes have already reached the consumer market, while organic solar cells and transistors are rapidly maturing. One of the great benefits with this class of materials is that they can be processed from solution. This enables several very cheap production methods, such as printing and spin coating, and opens up the possibility to use unconventional substrates, such as flexible plastic foils and paper. Another great benefit is the possibility of tailoring the molecules through carefully controlled synthesis, resulting in a multitude of different functionalities. This is very interesting for nano applications, where devices are made of a small number of molecules or even a single molecule, and were the molecules can be designed to self-assembly.

This thesis reports how charge transport can be altered in solid-state organic electronic devices. This is done from both a dynamic perspective, as in impedance switch devices, and from a static perspective, as in the modification of electrode properties to improve charge injection. The first six chapters give a brief review of the field of solid-state organic electronics, with focus on electronic properties, impedance switch mechanisms and architecture.

Paper I and III treat Rose Bengal switch devices in detail- how to improve these devices for use in cross-point arrays (paper I) and the origin of the switch effect (paper III). Paper II investigates how the work function of a conducting polymer can be modified to allow for better electron injection into an organic light emitting diode.