Lead carbanion anchoring for surface passivation to boost efficiency of inverted perovskite solar cells to over 25%

In this study, we synthesize lead carbanion complex to act as interface passivator for inverted perovskite solar cells. The strong Pb-C- bond between carbanion and lead-rich perovskite surface can stabilize the underlying perovskite to reduce defects and hence enhance photovoltaic performance. The carrier transfer behavior as a function of the lead carbanion complex was measured to optimize device performance by surface passivation. The devices achieved a power conversion efficiency of 25.16 % with a high open-circuit voltage of 1.17 V and a minimal voltage loss of 0.38 V. The perovskite solar cells with carbanion passivation maintained high performance over 600 h and had a lifespan in air exceeding 90 days without encapsulation. Our work introduces a new class of carbanion passivators to simultaneously improve the efficiency and stability of perovskite solar cells.