POLYMER - (BEDT-TTF) POLYIODIDE COMPOSITES

Preparation and properties of reticulate doped polymers containing BED T-TTF polyiodide crystalline network are discussed. The highly conduct ing films are obtained using different methods, including recently dev eloped one in which oxidation of the donor with iodine and crystalliza tion of the resulting salt take place simultaneously in situ, in the s wollen polymer matrix. It was found that the temperature dependence of conductivity of the separated microcrystal grown in the film exhibits metallic character with a maximum around 100K. The conductivity of th e as-obtained composite increases with temperature up to ca. 120K with an activation energy of ca. 50 meV, then levels off. Annealing of the composites in order to transform the BEDT-TTF polyiodide crystallites into superconducting beta-phase causes dramatic changes in the condu ctivity behaviour; the sigma(T) dependence of the composite switches f rom semiconductor- to metal-like. Stability of the films at ambient co nditions is good.