Customizing a Chemical and Field‐Effect Passivation Strategy for Efficient and Durable Perovskite Solar Cells Using Inorganic 2D/2D Nanocomposites

ABSTRACT Trap‐assisted charge recombination caused by grain boundaries and interface defects in polycrystalline perovskites remains a key obstacle to improving the efficiency and stability of perovskite solar cells (PSCs). Inorganic 2D/2D black phosphorus‐graphene oxide (BP‐GO) composites are regarded as an ideal “chemical and field‐effect passivation (CFP)” material for promoting photovoltaic (PV) performance and commercial conversion due to their ultrafast charge transfer, high work function, and excellent stability. On the basis of preliminary experiments, this work proposes a perovskite recrystallization strategy controlled by BP‐GO, and deeply explores the synergistic improvement mechanism of BP‐GO on perovskite surface energy, band alignment, electric field distribution/intensity, carrier dynamics, and device PV performance from the perspective of CFP. Combining theoretical and experimental results, the crystallization/growth process of the BP‐GO induced perovskite and the specific CFP principle are elaborated in detail. Benefiting from the positive factors triggered by the CFP effect of BP‐GO, a novel planar PSC with an efficiency of up to 25.17% is obtained. The corresponding unencapsulated devices demonstrate excellent environmental, long‐term storage, and operational stabilities. This work provides key scientific basis and low‐temperature design strategies for understanding the CFP engineering of inorganic 2D/2D composites and improving the performance of perovskite‐based optoelectronic devices.