organic solar cells (OSCs): (i) the simple parallel RC model, which
results in perfect semicircular cole–cole diagrams, (ii) the parallel
R-CPE model used in [21], that results in depressed circular
diagrams. This circuit includes an extra
fitting parameter to model
non ideal non-homogeneities such as porosities, roughness and
surface states (iii) The Mani parallel model [22], which consists in a
parallel R1CPE1 in parallel with a series combination of R2 and a
second constant phase element CPE2, (iv) Belmonte transmission
line model, which includes distributed transport resistors, Rt,
standing for carrier transport, and a distributed chemical capacitance
Cm, in parallel with a recombination resistance Rrec