A novel strategy to prepare conducting LB films based on TTF derivatives

A new method is described for the preparation of conducting Langmuir-Blodgett films based on tetrathialfulvalene (TTF) derivatives without long alkyl chain substitution. The mixed molecular system of behenic acid (BA) and oxygen-substituted TTF-type donor molecules such as 4,5-ethylenedioxy-4′,5′-ethylenedithio-tetrathiafulvalene (EOET) or bis-ethylenedioxy-tetrathiafulvalene (BO) provides a stable bilayer film at the air/water interface. In the LB films prepared by Y-type deposition, the donor molecules form mixed-valence dimers such as D⁺ D⁰, without secondary treatments. The maximum conductivities of the LB films reached 1.0S cm⁻¹ (EOET + BA) and 25 S cm⁻¹ (BO + BA) at room temperature. The surface pressure/area isotherms and Fourier transform infra-red spectra are also reported with regard to, respectively, film formation on the water surface and the mixed-valence dimer state under different molar ratios of the donors to B A.