New transparent, colorless, metallically conductive polymer films and their electrochemical transformations

New surface conductive polymer composite films exhibiting extraordinary properties: high conductivity with metallic temperature dependence and exceptionally high transparency are presented. The conducting networks in these materials are formed of plate-like nanocrystals of bis(ethylenedioxy)tetrathiafulvalene (BEDO-TTF) salts with iodine or bromine. The films with bromine salts are colorless and transparent while those with iodine are colored. It is demonstrated that colored films with (BEDO-TTF)/iodine networks can be electrochemically transformed into highly transparent, practically colorless materials without deterioration of the conducting network. The resulting metallically conducting polymer materials show the highest transparency among conductive composites reported so far.