Dynamic Behavior of Ionic and Electronic Phenomena in Perovskite Solar Cells Analyzed Through Poles and Zeros of the Transfer Function of Impedance

Understanding the physics of perovskite solar cells (PSCs) is crucial for their development. For this reason, we investigate the frequency-dependent response of PSCs aided by an electronic equivalent circuit to distinguish between ionic and electronic behavior at the interfaces and the bulk materials of the cells, respectively. The dynamic behavior of both effects is analyzed in terms of voltage drop within the solar cell as a function of source voltage. It is observed that higher quality PSCs show a sharp transition from ionic to electronic behavior as voltage increases, whereas lower quality PSCs show a smooth and slow transition. Also, the analysis of poles and zeros of the transfer function of impedance as a function of bias voltage reveals the point where the ionic behavior at the interfaces becomes irrelevant and the electronic properties in the bulk become dominant in terms of impedance and voltage drop. Therefore, the analysis of poles and zeros becomes a viable and novel characterization technique to investigate the dynamic behavior of bulk and interface phenomena in PSCs.