Unveiling the surface-interface properties of perovskite crystals and pivotal regulation strategies

Metal-halide perovskite solar cells have garnered significant research attention in the last decade due to their exceptional photovoltaic performance and potential for commercialization. Despite achieving remarkable power conversion efficiency of up to 26.1%, a substantial discrepancy persists when compared to the theoretical Shockley–Queisser (SQ) limit. One of the most serious challenges facing perovskite solar cells is the energy loss incurred during photovoltaic conversion, which affects the SQ limits and stability of the device. More significant than the energy loss occurring in the bulk phase of the perovskite is the energy loss occurring at the surface-interface. Here, we provide a systematic overview of the physical and chemical properties of the surface-interface. Firstly, we delve into the underlying mechanism causing the energy deficit and structural degradation at the surface-interface, aiming to enhance the understanding of carrier transport processes and structural chemical reactivity. Furthermore, we systematically summarized the primary modulating pathways, including surface reconstruction, dimensional construction, and electric-field regulation. Finally, we propose directions for future research to advance the efficiency of perovskite solar cells towards the radiative limit and their widespread commercial application.