Perovskite/crystalline silicon tandem solar cells have the potential to reach efficiencies beyond those of silicon single-junction record devices. However, the high-temperature process of 500 degrees C needed for state-of-the-art mesoscopic perovskite cells has, so far, been limiting their implementation in monolithic tandem devices. Here, we demonstrate the applicability of zinc tin oxide as a recombination layer and show its electrical and optical stability at temperatures up to 500 degrees C. To prove the concept, we fabricate monolithic tandem cells with mesoscopic top cell with up to 16% efficiency. We then investigate the effect of zinc tin oxide layer thickness variation, showing a strong influence on the optical interference pattern within the tandem device. Finally, we discuss the perspective of mesoscopic perovskite cells for high-efficiency monolithic tandem solar cells. Published by AIP Publishing.
Applied Physics Letters, vol. 109 (23), p. 4, Dec 2016.