2D-Antimonene-assisted hetero-epitaxial growth of perovskite films for efficient solar cells

There are many grain boundaries and defects in polycrystalline perovskite films, resulting in sacrificed efficiency and instability for perovskite solar cells (PSCs). By regulating the growth of perovskite grains along the vertical direction through epitaxial growth, one may expect fewer grain-boundaries, effective charge transport, improved crystalline quality, and reduced defect density. However, there is still no suitable epitaxial growth substrate for perovskite. Here, we developed an electrochemical lithiation intercalation and ultrasonication method to prepare high-quality antimonene nanosheets (ANs). It is found that the perovskite film grows preferentially along the (012) planes of the ANs that have perfect lattice match with the (001) planes of the perovskite, leading to a high-quality perovskite film with a preferential orientation along the [001] direction and greatly enlarged grain size. Consequently, the oriented perovskite-based PSC achieves a remarkable PCE of 24.54% and shows an enhanced stability under ambient conditions, thermal annealing or light illumination. This work opens an effective avenue to effectively control the oriented growth of perovskite film for high-performance perovskite optoelectrical devices.