Conducting Langmuir-Blodgett films of heptadecylcarboxymethyl-BEDT-TTF

Surfactant compounds containing the bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) donor group appeared to be very promising for production of highly conducting Langmuir-Blodgett (LB) films. A new donor compound, i.e. heptadecylcarboxymethyl-BEDT-TTF, is used to increase interaction of the molecules with water. It possesses donor properties of hexadecyl-BEDT-TTF and contains a strong hydrophilic group which does not prevent close packing of BEDT-TTF fragments due to its small dimensions. As a result, uniform highly conducting LB films of heptadecylcarboxymethyl-BEDT-TTF are deposited from the water subphase containing FeCl3. Conductivity of the films reaches 4 ohm−1 cm−1. Electron and small-angle X-ray diffraction studies are carried out. Some structure parameters are determined. Proceeding from these data possible structure models are proposed and peculiarities of the structure are discussed. The films are sensitive to the effect of electron beam and lose conductivity under irradiation. Thus, a desirable insulating pattern can be created in the conducting material which is important for technological applications.