oxidation–reduction cycles in a relatively wide potential
interval (i.e. from 0.50 to 1.60 V) while the second consists
on conventional consecutive galvanostatic charge/discharge
cycles. In both cases the stability of the 3-layered/
C8-SH ultracapacitor was the highest, the performance of
this assembly being exceptionally good when it is evaluated
using charge/discharge cycling (i.e. the SC after 2000
consecutive cycles is 80 F g1).
Octanethiol also affects the superficial morphology of
the 3-layered film, enhancing both the roughness and
porosity. These effects are transmitted layer-by-layer from
the internal one to the external one. Thus, the internal and
the intermediate layers act as nanometric templates of the
intermediate and external layers, respectively, in the electrogeneration
process. Measures of the thickness, roughness
and porosity are fully consistent with this growing
mechanism and the mobility of the perchlorate anions.
The porosity, which was estimated by comparing the
thickness of the films before and after electrochemical degradation,
is 35% higher for 3-layered/C8-SH than for PEDOT/
steel. Finally, EIS measures have been used to get
additional information about the resistance and capacitance
of the 3-layered devices, results being fully consistent
with the electrochemical and structural
observations. The overall of the results indicate that multilayered
films of PEDOT and PPy deposited on steel coated
with octanethiol are effective organic ultracapacitors.