3D-hybrid networks with controllable electrical conductivity from the electrochemical deposition of terthiophene-functionalized polyphenylene dendrimers.

Upon electrochemical oxidation the hedgehogtype core-shell system 1 forms a network which can be charged and discharged in the potential range between 0.4 and 1.5 V. In-situ conductivity measurements (Figure 1) of the coupling product of 1 show an increase of the conductivity during voltammetric charging of the thiophene chains in the deposited material. This conductivity passes a maximum approximately at the half-charged level. At higher potentials the conductivity increases again indicating a three-dimensional charge transport. Obviously, the hopping processes of charge carriers are facilitated in the 3D network. The results offer new insights into conductivity mechanisms of conjugated polymers. The great similarity between the conductivity behaviour of this material and that of radical ion salts supports the view of almost identical transport mechanisms.