Bismuth barrier solves unexpected copper corrosion in perovskite solar cells

⚡ AI Executive Summary

Researchers at the Chinese Academy of Sciences identified a significant degradation mechanism in copper-electrode perovskite solar cells: edge corrosion caused by iodide ions migrating from light-induced perovskite decomposition and reacting with copper to form corrosive compounds. This finding challenges the cost-effectiveness assumption behind copper electrode adoption, as the cells lose efficiency rapidly despite initial optimization efforts with molybdenum trioxide buffer layers. The team developed a protective bismuth interlayer that blocks iodine diffusion and prevents copper-iodide formation, substantially improving operational stability. For photovoltaic engineers, this research highlights a critical materials-science challenge in scaling cost-reduced perovskite architectures: the interplay between electrode composition, interface chemistry, and light-induced ion migration can nullify cost savings if degradation pathways are not addressed. The work demonstrates that protective barrier design—informed by precise microscopy and photoluminescence mapping—remains essential to commercializing next-generation solar technologies, even when primary efficiency metrics appear competitive with conventional approaches.