Interface charge accumulation dynamics in 3D and quasi-2D perovskite solar cells

Perovskite solar cells (PSCs) have rapidly developed in recent years with the advantages of high efficiency and low cost. Although PSCs are the fastest-advancing solar technology to date, bottlenecks such as J-V hysteresis have limited the further development significantly. In this work, we have investigated the in-depth mechanism of hysteresis in both three-dimensional (3D) and quasi-2D (Q-2D) planar p-i-n PSCs. We conducted scanning-rate-dependent and temperature-dependent measurements to distinguish the ion migration and the capacitive charging. The coefficient for capacitance and pseudocapacitance from the J-V curves are further employed to analysis the hysteresis. It is found that both capacitance and ion migration contribute to the J-V hysteresis, but play different roles in 3D and Q-2D perovskite devices. In 3D PSCs, the ion migration has substantial impacts on the J-V hysteresis, wherein ions are tending to move. While in the Q-2D PSCs, the capacitance extends the characteristic charging time, which is mainly responsible for J-V hysteresis. These findings will help to effectively suppress the hysteresis for 3D and Q-2D PSCs, eventually benefiting device performance and long term stability.