Electrical conductivity of alpha-Quinquethiophene Stearic acid Langmuir-Blodgett films doped with iodine.
01 January 1986
Langmuir-Blodgett films consisting of 0-62 mol % purified alpha- quinquethiophene (QT) in cadmium stearate-stearic acid (ST) were deposited on glass substrates and characterized by a variety of methods. Exposure of these films to iodine vapor rendered them electrically conductive, the conductivities being strongly dependent on QT concentration and the number of layers deposited.
The most conductive samples (>35 mole % QT, >~10 layers) had siguna = 0.2 S cm(-1). The concentration dependence of the conductivity can be broadly described by the two-site percolation models that take into account the specific chain arrangement and finite conductivities of both QT and ST aggregates in the films. Finally, the relevance of the QT-ST system to other conducting materials is discussed.