Preventing Hysteresis in Perovskite Solar Cells by Undoped Charge Blocking Layers

Preventing hysteresis in lead halide perovskite solar cells remains one of the key challenges hindering their integration into industrial applications. Herein, we numerically study a model solar cell system that is based on a mixed electron–ion conducting perovskite active layer and vary the configuration of undoped charge-blocking layers within the device. We find that the use of undoped blocking layers significantly reduces the potential drop across the perovskite active layer. This redistribution of voltage across the device suppresses the ion accumulation, or deficiency, which would otherwise develop at the two ends of the active layer. The fill factor is not compromised, provided that the blocking layers’ mobility value is not lower than 0.01 cm 2 V –1 s –1, which results in devices with power-conversion efficiencies surpassing 20% and minimal hysteresis. We believe that this method not only can suppress hysteresis effectively but could also contribute to the long-term stability of such cells that have been shown to be adversely affected by ion migration.