Large-Sized High-Efficiency Fiber Perovskite Solar Cells Fabricated by Automatic Thin-Film Coating on Curved Surfaces

Perovskite solar cells in a fiber format have great potential for wearable electronics due to their excellent flexibility, efficient light harvesting, and potentially high power conversion efficiency (PCE). However, the fabrication of large-sized fiber perovskite solar cells (FPSCs) while maintaining high efficiency remains a major challenge because of the difficulty in the formation of uniform crystalline perovskite films on highly curved surfaces. Here, we report a scale-up automatic approach for the fabrication of large-sized FPSCs via sequential coating of active layers on fiber substrates and posttreatment of perovskite films. We focus on understanding the perovskite film formation process on fibers and manage to control the film thickness, morphology, and crystallinity by adjusting the coating speed, precursor solution aging time, and posttreatment. As a result, a 20.0-cm-long FPSC with a PCE of 7.63% is achieved, and this length is almost ten times longer than those of the previously reported FPSCs. Our work represents a breakthrough in fabricating large-sized high-efficiency FPSCs, which will ultimately lead to practical applications of FPSCs.