Evolution of Performance Parameters of Perovskite Solar Cells with Current–Voltage Scan Frequency

Abstract

Current–voltage measurements are a standard testing protocol to determine the efficiency of any solar cell. However, perovskite solar cells display significant kinetic phenomena that modify the performance at several time scales, due to hysteresis, internal capacitances, and related mechanisms. Here, we develop a method to analyze the current–voltage curves by using large amplitude sinusoids as the excitation waveforms, specifically addressed to determine the influence of cycling frequency on relevant performance parameters. We solve a system of equations representative of charge collection and recombination, that provide the frequency-dependent dynamical behavior of the internal ion-controlled surface recombination processes that cause open-circuit voltage variations often observed in high performance devices. We analyze several reported experimental data pertaining to state-of-art devices, and we showcase the key parameters governing the evolution of hysteresis phenomena as the scan speed is increased in relation to Impedance Spectroscopy.