The dominant role of memory-based capacitive hysteretic currents in operation of photovoltaic perovskites

The potential opportunities of perovskite-based technology to further advance in the photovoltaic field and implement an extensive industrial application, will mainly depend on whether some of its weaknesses, such as current density-voltage (J?V) hysteresis, can be overcome. In this sense, a critical aspect is the understanding and the subsequent accurate description of hysteresis in perovskite cells. Here, we present the theoretical underpinnings to interpret non-ideal transient dynamics in stepwise-JV measurements, using electrical analysis strategies and fractional calculus tools. Our model was validated with experimental measurements of CsFAPbIBr-based photovoltaic perovskites of different active layer thicknesses with persistent long-range time photocurrents. It is reported that hysteresis phenomena increase with more pronounced non-ideal capacitive effects suggesting that more trapping events limit ion motion and carrier transport. Our main interest is to provide valuable information about the memory-based slow timescale dynamics, which exhibits a significant impact on the appearance of hysteresis and, to a large extent, on the operation of the solar cell. ? 2020 Elsevier Ltd