Rectifying interfaces using two-layer films of electrochemically polymerized vinylpyridine and vinylbipyridine complexes of ruthenium and iron on electrodes

Article abstract of DOI:10.1021/ja00391a001

Polymerization of the complexes [Ru(bpy)₂(vinyl-py)₂]²⁺ (I), [Ru(vinyl-bpy)₃]²⁺ (II), [Ru(bpy)₂(vinyl-bpy)]²⁺ (III), [Ru(bpy)₂(vinyl-py)Cl]⁺ (IV), and [Fe(vinyl-bpy)₃]²⁺ (V) can be initiated by electrochemical reduction in CH₃CN solvent to produce stable, adherent, electrochemically active films on Pt, vitreous carbon, SnO₂, and TiO₂ electrodes. Randomly site-mixed copolymer (one-layer) and spatially segregated two-layer films of the pairs I and IV and II and V can be prepared by simultaneous and sequential polymerization of the appropriate monomers, respectively. The spatial features were confirmed by variable-angle X-ray photoelectron spectroscopy. Cyclic voltammetry of the copolymers is the additive response of the two redox components. In the two-layer films, however, oxidation state changes of the outer polymer films are constrained to occur via electron-transfer mediation by the inner polymer film. The result is a rectifying property of the polymer two-layer interface which should be useful in mimicking electronic device behaviors such as Zener diodes.