Fast and Simple Series Resistance Imaging for Tandem Solar Cells Using Differential Luminescence

The development of new advanced imaging techniques is essential to enable industry and photovoltaic research to develop ever more efficient devices. For example, the identification and spatial localisation of defects is crucial to understand how to adapt lab scale cell manufacturing recipes (around 1 cm 2 ) for the production of industrial‐sized cells (above 243 cm 2 ). More specifically, for perovskite/silicon multijunction devices, advanced defect imaging provides a better understanding of areas impacted by stability and ageing issues. This article introduces and validates a new, calibration‐free series resistance imaging technique for the determination of transport losses within the solar cell. This method, based on differential luminescence imaging, is first illustrated on a single junction perovskite cell. Then, the technique is successfully applied to a perovskite/silicon monolithic tandem solar cell for the detection and the identification of resistive defects within the perovskite subcell. This practical and powerful characterisation method is fast, non‐destructive, and relatively simple to implement. Therefore, it could promptly be used by photovoltaic industry and research to support the development of emerging technologies.