From Ultrafast to Ultraslow: Charge-Carrier Dynamics of Perovskite Solar Cells

Despite the rapid development in the past years, performances of the perovskite solar cell are still limited by the photovoltage and fill factor that are mainly determined by the charge-carrier dynamics. In this review, the charge-carrier dynamics of the cell in a wide time span are summarized and discussed to provide a comprehensive understanding of the optoelectronic processes of the perovskite material and devices. Generally, free carriers are generated rapidly and dominate the following transport and recombination processes that mainly occur within a microsecond time scale. The relatively slow defect and ion dynamics and their characteristic time have also been presented. A physics stability regarding this cell is proposed based on understanding the ion dynamics, and the significance of regulating ion and electron dynamics is highlighted. We finally emphasize that elucidation of the band-edge energy structure and charge nature of the perovskite is still an open question.