Microwave and d.c. conductivity of α-ET2I3 and βt-ET2I3 microcrystals in polymer films

Electrical properties of conducting polymer films containing an ET2I3 (ET=bis(ethylenedithiolo)tetrathiafulvalene) polyiodide crystalline network have been investigated. It is shown that the conditions of preparation of these films, i.e., time of exposition to solvent iodine vapours, concentration of iodine in solvent, time and temperature of annealing, have a very strong influence on the conducting properties of the films. By choosing proper preparation conditions one can obtain conducting composites showing the conductivity behaviour characteristic of α-ET2I3 or βt-ET2I3 single crystals.