Visualizing Macroscopic Inhomogeneities in Perovskite Solar Cells

Despite the incredible progress made, the highest efficiency perovskite solar cells are still restricted to small areas (<1 cm²). In large part, this stems from a poor understanding of the widespread spatial heterogeneity in devices. We overcome these limitations by using luminescence imaging to reveal large, millimeter-scale heterogeneities in the inferred electronic properties. We determine spatially resolved maps of ‘charge collection quality’, measured using the ratio of photoluminescence intensity at open and short circuit. These methods are applied to quantify inhomogeneities introduced by a wide range of transport layers, ranking them by suitability for upscaling. Our findings suggest that top-contacting transport layers are the dominant source of heterogeneity.

ACS Energy Letters, 7(7)