Electrochemistry of Polymer Films Not Immersed in Solution. Electron Transfer on an Ion Budget

Films of poly-(Os(bpy)2(vpy)2)(C104)2 sandwiched between two metallic electrodes can support electron hopping, concentration gradient-driven electron conduction in acetonitrile vapor and in dry N2 gas, when the potential difference delta E between the electrodes is made such as to generate a mixture of Os(III), Os(II), Os(I) states. The latter requirement is dictated by the fixed pool (ion budget) of C10(-)4 counterions in the film. It is significant the C10(-)4 ions can move relatively freely in the dry film, that the apparent Os(III/II) and Os(II/I) formal potentials are different for the vapor and dry N2 environments, and that currents through dry polymer films are larger than in vapor exposed films.