Highly Efficient Perovskite Solar Cells with Neglectable Hysteresis and Increased Open Circuit Voltage via a Nickel Chloride Interface Modification

Interface modification engineering has been widely used as a flexible and effective method to optimize the performance of perovskite photovoltaic devices. Herein, we adopt NiCl2 as a modifier to passivate the interface at the electron transporting layer (ETL) and perovskite layer to drive high-efficiency perovskite solar cells (PSCs) with increased open circuit voltage (Voc) and neglectable hysteresis. The devices based on SnO2/NiCl2 ETL achieved a high Voc (1.17 V) and power conversion efficiency (PCE) (19.46%). The improvement is attributed to the increased energy level of the conduction band minimum (ECBM) and reduced defect states by NiCl2 interface modification. Our findings provide an effective way to obtain higher Voc and PCE values as well as neglectable hysteresis for planar PSCs.