Luminescence Imaging of Perovskite Solar Cells

At the lab scale, perovskite solar cell efficiencies (~25%) now rival crystalline silicon. Translating such high-efficiency lab technology to the wafer scale demands an understanding of the origins of spatial heterogeneities in the cell. We analyse a number of device architectures using luminescence imaging, and quantify the heterogeneity that is introduced when a transport layer contacts the perovskite. We are thus able to provide a ranking of all widely used transport layers by suitability for upscaling. Furthermore, while it is well-known that spatially resolved voltage losses can be reconstructed from luminescence measurements, no such method is yet available for current losses. We demonstrate that the ratio of luminescence quantum yields at short circuit and open circuit is an excellent predictor of current loss. We thus, for the first time, able to reconstruct spatial maps of all PV parameters from luminescence measurements. We suggest that these ideas can be used to accelerate the development of highly-efficient, large area devices, especially through high-throughput experimentation.