Electrical properties of 1,4-bis[2-(3,4,5-trimethoxyphenyl)ethenyl] benzene

The increase of the electrical conductivity of the arylenevinylene (AV) system 1,4-bis[2-(3,4,5-trimethoxyphenyl)ethenyl] benzene was measured as a function of the doping level of iodine. Compressed powders and films blended with polystyrene (PS) containing up to 30 wt.% of the oligomer were used. At the highest doping level the conductivity of the compressed powder reaches a value of <F>3.3×10−4</F> Ω−1 cm−1. The conductivity, measured between 90 and 300 K on the powder with the highest conductivity, is thermally activated with an activation energy of ∼0.1 eV. The thermopower is positive in agreement with a charge transfer from the organic chain to an iodine atom. Its value is small (25 μV K−1) and temperature independent. The results are interpreted in terms of small-polaron hopping. [Copyright &y& Elsevier]