A uniform and full coverage perovskite film is of significant importance for flexible perovskite solar cells. In
this study, highly efficient flexible perovskite solar cells were assembled using a flexible conductive plastic
substrate by a one-step gas pump drying method to prepare high performance perovskite films under air
conditions. The SEM results show that the perovskite film deposited on the flexible conductive plastic
substrate was uniform, compact, and pinhole-free. The AFM results show that the film presented an
extremely smooth surface morphology with a root mean square roughness of 15.8 nm in a large and
representative scan area of 18 18 mm2. The flexible planar perovskite solar cell was fabricated, and all
devices were prepared at 100 C or below under air conditions. The highest efficiency on flexible
substrates had reached 11.34% with an average efficiency of 8.93% for 14 solar cell devices.