Solvent-additive cascade engineering enables single-oriented perovskite films with facet-driven performance and stability

Abstract

Facet engineering is an important strategy for enhancing the efficiency and stability of perovskite devices. However, the formation of high-quality, tunable crystal facets remains a challenging endeavor. Here, we employed a novel solvent-additive cascade regulation (SACR) strategy to create homogenous orientations via a two-step method. Mechanistic analysis reveals that solvents drive orientation via topochemical assembly, while additives regulate specific facet growth through differential bonding intensities with crystal nuclei. With the SACR method, we successfully obtained perovskite films with homogeneous (111) and (100)-oriented facets following the Wulff construction rule. The resulting n–i–p structured devices achieved optimal efficiencies of 23.32% and 25.33%, respectively. Notably, the (100)-oriented devices exhibited superior photoelectric performance, whereas the (111)-oriented devices demonstrated better long-term stability. This work underscores the critical role of facet engineering in tailoring the optoelectronic properties and structural stability of perovskite films, offering a viable pathway toward efficient and durable perovskite solar cells.