Semifluorinated TTF derivatives in Langmuir-Blodgett films

New semifluorinated tetrathiafulvalene (TTF) derivatives were prepared and used in Langmuir and Langmuir-Blodgett (LB) films. Transfer onto a solid substrate of such pure monolayers can be easily achieved leading to organized LB films in which the fluorinated chains are tilted with respect to the normal of the substrate as demonstrated by infrared and X-ray experiments. Doping of such films by iodine does not induce change in the layer spacing on the contrary to already published studies concerning alkyl derivatives of TTF. Such structural stability and values of the layer thickness suggest some interdigitation between TTF groups within the LB film. Depending on the exact chemical structure of the TTF moiety, the iodination is stabilized or not. When the doped film is stabilized in a mixed valency state, conductivity of approx. 10⁻² S cm⁻¹ was measured at room temperature.