Reductive cation for scalable wide-bandgap perovskite solar cells in ambient air

High-performance wide-bandgap (WBG) perovskite solar cells are expected to play a key role in next-generation multi-junction solar cells. However, several challenges remain to be overcome, such as large photovoltage loss, poor stability and scalable fabrication in ambient air, which hinder the commercialization of this technology. Here we incorporate a reductive methylhydrazinium cation into WBG perovskites, which not only reduces defect density but also suppresses iodide oxidation and halide demixing, enabling scalable fabrication of efficient and stable WBG solar cells and modules in ambient air. Remarkably, the champion WBG perovskite solar cells achieve a power conversion efficiency (PCE) of 23.3% with an open-circuit voltage of 1.28 V, corresponding to a record low voltage loss of 0.37 V. The WBG mini modules deliver a stabilized PCE of 19.8% with an aperture area of 25 cm2. The mini modules can keep 94% of the initial PCE after 700 hours of operation under continuous light soaking at 1-sun illumination at 55 ± 5 °C. This work suggests a viable route to the sustainable harvesting of solar energy. Wide-bandgap perovskites are critical to tandem solar cells for maximized solar energy capture and efficiency, but their stability remains a major issue. Here, by introducing reductive cations, the authors realize scalable fabrication of large-area solar cells in ambient conditions with good performance.