As the two resistances employed in the matryoshka circuit exhibit higher resistances at the high photocurrent region (Figure ), indicating that both are somehow related to the recombination current, we labeled them as Rrec1 and Rrec2. A higher recombination resistance means a reduced recombination due to the increased band bending when going from flat band to depletion in the photoabsorber, which more effectively separates the photogenerated charge carriers. The fact that Rrec1 and Rrec2 have very similar trends as a function of applied potentials suggests a common origin for both resistances. In terms of kinetics, however, they are coupled with different capacitive elements, resulting in completely different time constants. A plausible explanation for Rrec1 and Rrec2 is that both resistances are related to a recombination process at the Sb2Se3/TiO2 interface, similar to what was observed in the perovskite/TiO2 interface by Zarazua et al. In the perovskite/TiO2 system, two semi-circles were attributed to the multistep recombination at the perovskite/TiO2 interface by analyzing the EIS data with the matryoshka circuit. The possible origin of the multi-step recombination was suggested as Schottky-Read-Hall trap-mediated recombination. We also presume that the Cinter is related to the charge accumulation at the Sb2Se3/TiO2 interface similar to the charge accumulation capacitance at the perovskite/TiO2 interface, because both semi-circles are observed in a similar frequency range (~1Hz) in addition to the fact that they have an inverse relationship between the resistance and capacitance (increasing Rrec2 with decreasing Cinter and vice versa).