Dynamic interface charge governing the current-voltage hysteresis in perovskite solar cells.

The accumulation of mobile ions causes space charge at interfaces in perovskite solar cells. There is a slow dynamic process of ion redistribution when the bias is changed. The interface charge affects band bending and thus the photocurrent of the solar cells. Consequently the dynamic process of the interface charge governs the current-voltage hysteresis. Very low interface charge density leads to hysteresis-free devices.