Mixed valence self-assembled monolayers: Electrostatic polarizabilities of the mixed valence states

作者：Goeltz John C; Kubiak Clifford P^*

来源：Journal of Physical Chemistry C, 2008, 112(22): 8114-8116.

DOI：10.1021/jp802209u

Kelvin probe force microscopy is used to examine the electronic polarizability of self-assembled monolayers (SAMs) of mixed valence species. Tetrathiafulvalene (TTF)-based SAMs exhibit much greater polarizability in the delocalized monocationic state. A TTF(+)PF(6)(-) SAM exhibits 61% of the capacitance of the neutral SAM, and a charge transfer complex with tetracyanoethylene exhibits 63%. The large difference relative to the neutral SAM is attributed to the delocalized electronic charge in the mixed valence cation, which creates an internal dipolar field that offsets the applied electric field. Comparison of ferrocene- and ferrocenium-based monolayers shows that the major contribution to the polarizability of the TTF system is the delocalized electronic structure and not the charge-separated ionic state.

• 出版日期2008-6-5