Efficient perovskite solar cell on steel enabled by diffusion barrier and surface passivation

While many state-of-the-art perovskite solar cells (PSCs) have been realized on rigid glass substrates, demonstrating perovskite cells on other types of surfaces may give rise to new applications. Here, we successfully demonstrate efficient PSCs on steel. The role of an indium tin oxide interlayer as a barrier against iron diffusion from the steel substrate is elucidated. We further show that the performance of the perovskite device on steel can be improved by using an n-octylammonium bromide passivation layer, achieving a power conversion efficiency of 17.1%. To the best of our knowledge, this is the highest reported for perovskite cells on steel. This work demonstrates the robust design necessary for PSCs on steel and the versatility of PSCs. It may also inspire work on other types of surfaces beyond glass, paving the way for a wider range of applications.