Thus far, we have successfully investigated the properties of buried semiconductors and junctions in multi-layered photocathodes under operando conditions by impedance spectroscopy. By measuring and fitting the EIS data of Sb2Se3 photocathodes, we can interrogate each layer in the stack: the surface catalyst, TiO2 and Sb2Se3. The lowest frequency RC element is associated with the charge transfer reaction, corroborated by the time constant as obtained from transient photocurrent measurements. The potential dependence of the capacitances and doping densities from the Mott-Schottky plots matched the literature values of TiO2 and Sb2Se3, providing evidence for their correct assignment. Thus, the simple model in Figure -b accurately represents the photophysical and electrochemical processes of the system under study. We expanded the application of the model to photocathodes based on other classes of materials, crystalline Si and Cu2O. The EIS method allowed us to directly compare the minority carrier lifetimes of each device under operando conditions. It was revealed that Si photocathodes have longer lifetimes than Sb2Se3 and Cu2O photocathodes. Our work has demonstrated the versatility of the EIS method in analyzing multi-layered photocathodes with various classes of photoabsorbers under real operational conditions.