Interplays between charge and electric field in perovskite solar cells: charge transport, recombination and hysteresis

Interplays between charge and electric field, which play a critical role in determining the charge transport, recombination, storage and hysteresis in the perovskite solar cell, have been systematically investigated by both electrical transient experiments and theoretical calculations. It is found that the light illumination can increase the carrier concentration in the perovskite absorber, thus enhancing charge recombination and causing the co-existence of high electric field and free carriers. Meanwhile, the cell shows a similar charge storage and junction mechanism to that of the multicrystalline silicon solar cell, where the junction electric field determines the charge collection and distribution. Furthermore, it is demonstrated that the static charge of both the doping and defect coming from ion (vacancy) migration can significantly influence the electric field inside the cell, thus affecting the charge collection and recombination, which could be the origins for the widely-concerned hysteresis behaviors.