Interfacial Engineering for Improved Stability of Flexible Perovskite Solar Cells

Because of unique optoelectronic properties, such as extended carrier lifetime, large absorption coefficient, high defect tolerance factor, low exciton binding energy, and ambipolar diffusion, metal halide perovskites display enormous potential for the next generation of photovoltaics. Flexible perovskite solar cells with low weight, high flexibility, and conformability have attracted attention for portable electronic products. The interface is crucial in perovskite solar cells for both photovoltaic efficiency and operational stability. A high-quality interface could be obtained through interface engineering. Here, we summarize the degradation mechanisms and review interfacial engineering with the emphasis on their effects in flexible perovskite solar cells. On the basis of recent research progress in flexible devices, current challenges, possible directions, and perspectives are discussed. This would be helpful to promote the commercialization of flexible perovskite solar cells.