By dramatically varying the values of parameters of the
impedance components of a DSC full-interface equivalent circuit
containing four interfaces and two layers, we have studied
the interaction between the charge interface transfer impedance
and interfacial transport impedance and its effect on the overall
impedance of the cell. The results show that some previously
ignored interfaces, such as the TCO/TiO2 and TCO/EL interfaces,
as well as Nernst diffusion impedance in the electrolyte solution,
can also influence the overall impedance characteristics of DSC
under certain circumstances. When the transfer resistance of the
TCO/TiO2 interface reaches 10 , the speed of the electron transfer
process may become a factor that inhibits the collection of electrons;
the impedance of DSC is not significantly influenced when
the capacitance of the TCO/TiO2 interface is changed by an order
of 103. When the transfer resistance of the TCO/EL interface is
small (1 ), the semicircle of the medium frequency range will
nearly vanish and only the Nernst diffusion impedance and EL/Pt-
TCO interface impedance are left. The impedance of DSC is barely
influenced when it rises to above 104. When the capacitance of
the TCO/EL interface is decreased by 1.5
×
10−6 F, the semicircle of
the TCO/TiO2 interface can be observed; when it is increased, the
impedance of DSC is barely influenced. When the dc resistance is
large enough, the Nernst diffusion impedance will coincide with
the impedance of the Dyed-TiO2/EL interface. As the characteristic
diffusion time decreases, it becomes more and more difficult to
observe the electrolyte diffusion impedance of the low frequency
range.