Electrochemical investigation on hybrid viologen tetracyanoquinodimethanide LB films

Positively ionized monolayers of 1,1′-dioctadecyl-4,4′-bipyridilium were prepared on aqueous solutions of tetracyanoquinodimethane in a mixed valence state. The floating films were transferred onto ITO electrodes, yielding hybrid multilayers containing both viologen cations and (TCNQ)2- anions. The electrochemical properties of these modified electrodes were studied by cyclic voltammetry and showed reversible electrochemical processes with quite negative formal potentials of the viologen units. The Γc/Γa ratio was 1 and the electrochemical activity was preserved beyond the first layer. A comparison study of the hybrid viologen/TCNQ LB films with other films incorporating other counterions was carried out and the differences attributed to chemical complexation and a different arrangement induced by the counterion incorporated in the films.