Conductive films of tetrathiafulvalene dicarboxylate cation radicals and poly(vinyl alcohol) formed by casting

Aqueous solutions of dipotassium tetrathiafulvalene dicarboxylate (1), potassium ferricyanide and poly(vinyl alcohol) were used to cast air-stable, flexible and electrically conductive films. Casting at 80–95 °C formed a network of microcrystals oriented in the film plane. Spectroscopic studies showed that these crystals contain π-stacks of the cation radical 1+. No evidence for mixed valence stacks was found. A film containing 5 wt.% of 1+ in PVA had a four-point conductivity σ = 10−2 S cm−1 in the film plane. The structural anisotropy led to a lower conductivity (10−4 S cm−1) across the plane of the film.