Quantitative Hyperspectral Luminescence Imaging Reveals Upscaling Losses in Perovskite Solar Modules

Perovskite solar cells have achieved remarkable progress over the past decade, with power conversion efficiencies approaching 27% on sub‐cm ² devices. However, translating these high efficiencies to large‐area modules remains a major challenge, as performance losses arise from nonuniformities in perovskite layers, interfaces, and interconnects. In this work, we present calibrated hyperspectral photoluminescence (PL) and electroluminescence (EL) imaging applied for the first time to a 64 cm ² perovskite mini‐module. This approach enables spatially resolved maps of the external quantum efficiency (EQE) derived from EL data alongside absolute maps of absorbance, quantum yield, series resistance, fill factor, and power conversion efficiency. By directly visualizing performance‐limiting regions and quantifying transport bottleneck, we identify resistive transport and interconnection‐related losses as the dominant limitations when upscaling from small‐area cells to series‐connected modules. A quantitative analysis of losses reveals that these extrinsic integration losses, taken together, account for a loss equivalent to that of intrinsic material losses, making it a clearly identified engineering target. This work demonstrates calibrated hyperspectral imaging as a powerful, non‐destructive diagnostic for guiding interconnect and materials optimization in high‐performance perovskite module development.