ITO-Free Flexible Perovskite Solar Cells Based on Roll-to-Roll, Slot-Die Coated Silver Nanowire Electrodes

For the roll to roll production of truly flexible, cost effective solar cells, alternatives are needed to replace indium tin oxide, which conventionally serves as the transparent electrode. In this work, silver nanowire/PEDOT:PSS based electrodes are processed onto PET substrates by a scalable, roll-to-roll slot-die process. These electrodes are extensively characterized and incorporated into ITO-free, flexible perovskite solar cells to achieve a champion efficiency of 11%, comparable to ITO controls on glass. Furthermore, all of the device layers, except the top electrode, were deposited under ambient conditions. Preliminary device bending tests showed negligible change in efficiency after 10 000 compressive bends to a 5 mm radius. This progress is key to the manufacture of cheap, flexible perovskite solar cells by low temperature processing techniques.