Researchers at Nanjing University, together with the Beijing Institute of Technology, the University of Victoria, and industry partners including Renshine Solar (Suzhou), Shandong Energy Group, China Three Gorges Corporation, Inner Mongolia Three Gorges Mengneng Energy, and Jiangsu Fangyang New Energy Investment, have reported certified efficiencies of 24.0% for a perovskite solar module with an 810 cm² aperture area and 22.0% for a module with a total area of 0.72 m². Both modules passed the full IEC 61215 reliability test suite, the international standard used to qualify the durability of terrestrial photovoltaic modules - results the team describes as the highest reported for scalable, industrially viable perovskite photovoltaics.
Surface passivation is a critical step in perovskite solar cell fabrication: defects at the boundary of the perovskite layer can trap charge carriers and accelerate recombination, lowering the voltage and current a device can extract from sunlight. Ammonium halides have become a popular class of passivator because they are effective at the laboratory scale, but they are sensitive to humidity and tend to distribute unevenly when a device is scaled up. Both problems are compounded during slot-die coating, the continuous, roll-to-roll-compatible deposition method used for large-area manufacturing, where variations in wetting, drying speed, and solvent evaporation can leave some regions over-treated and others under-passivated. Ammonium halides' sensitivity to moisture has generally forced manufacturers to process meter-scale perovskite modules inside an inert atmosphere, adding equipment complexity and cost. To avoid that constraint, the researchers engineered the perovskite film's surface chemistry before passivating it, rather than relying on the passivator to compensate for an unfavorable surface afterward.
Using a solvent system combining 2-methoxyethanol, 1,3-dioxolane, and dimethyl sulfoxide - chosen for its high saturation vapor pressure - they controlled the film's crystallization to produce a surface naturally enriched in formamidinium iodide. They then treated that tailored surface with lead dioleate, a chemically stable lead carboxylate, in place of a conventional ammonium halide. According to the study, the treatment both suppresses electronic defects at the interface and enhances carrier transport across it - addressing the passivation-versus-conductivity trade-off that can limit the benefit of a purely defect-blocking treatment layer.
Because lead carboxylates are more stable than ammonium halides under humid conditions, the approach is designed to be compatible with ambient-air processing rather than requiring a rigorously controlled inert environment throughout the production line. The researchers demonstrated the strategy at module scale rather than only on small laboratory cells, where interconnections between subcells and non-uniform current flow across a large substrate typically introduce additional losses not seen in single small-area devices. The reported 24.0% aperture-area and 22.0% total-area efficiencies, together with a full pass of IEC 61215 testing, indicate the passivation chemistry held up when translated from a research cell into a manufacturing-relevant architecture.
The researchers said the results demonstrate a manufacturing strategy that pairs deliberately engineered surface chemistry with a stable, ambient-compatible passivator, and that the approach could help close the gap between highly optimized laboratory perovskite cells and modules made by continuous, industrial-scale coating.
