The morphology and electrochemical properties of redox active films obtained by self-assembly of [Os(bpy)₂(PVP)₅Cl]Cl, bpy = 2,2’-bipyridyl and PVP = poly(4-vinylpyridine), on highly oriented pyrolytic graphite electrodes (HOPG) are measured. Films exhibit remarkable flat topographies, with molecular size fluctuations in height over several micrometers. These films displayed cyclic voltammograms characterized by rather narrow waves as a result of the lateral attractive forces between the adsorbed molecules. Prolonged adsorption times lead into a second growth regime, resulting in thicker films with height fluctuations as large as 100 nm. These results demonstrate that self-assembly is a simple and reproducible method for creating homogeneous molecularly flat films of this complex for incorporating into thin layer devices.

This work was carried out in the group of Prof. David J. Fermín.

References:

• E. Aslan, F. P. Campana, D. J. Fermín, H. Siegenthaler, F. Frehill, J. G. Vos;
  "Molecularly flat films of the redox [Os(bpy)₂(PVP)₅Cl]Cl complex obtained by spontaneous adsorption at HOPG electrodes"
  J. Electroanal. Chem., 599, 267–274, (2007); doi:10.1016/j.jelechem.2006.03.030.