An electrical investigation into multilayer assemblies of charge-transfer materials

Metal/Langmuir-Blodgett film/metal structures based on amphiphilic charge-transfer materials have been fabricated and the DC conductivity perpendicular to the plane of the film has been measured. Linear current-voltage behaviour was observed for small applied biases. In contrast, the high-field (>10⁵ V cm^-1) current against voltage characteristics exhibited a log (current) against voltage^0.5 dependence, similar to that measured for fatty acid multilayers. No evidence for rectification has been found in structures containing both donor and acceptor materials. However, devices incorporating a tetracyanoquinodimethane derivative invariably possessed output voltages with no applied bias; a significant dispersion in the low-frequency capacitance was also noted for these structures.