Highly Oriented Inch-Scale Monocrystalline 0D/3D Perovskite Heterojunction Films via Vapor-Phase Epitaxy for Self-Powered Photodetectors

While perovskite-based devices have been widely investigated, achieving scalable production of monocrystalline perovskite heterojunction films with high interfacial quality through in situ growth methods remains challenging, primarily due to inherent lattice incompatibility and pronounced anion migration issues. Here, we report the successful growth of a monocrystalline 0D/3D perovskite heterojunction film with an area of 6.25 cm² via a vapor-phase epitaxy technique. The structural compatibility between the 0D and 3D perovskite components results in heterojunction films with well-defined interfaces, exceptional crystallinity, and high uniformity, showing oriented growth along the (001) and (011) crystal facets. This heterojunction system facilitates the reconstruction of an asymmetric space-charge distribution and enables the dynamic passivation of halide vacancies in the 3D component, thereby enhancing electric field modulation and defect passivation. As expected, the resulting single-crystalline 3D/0D heterojunction film-based photodetector demonstrates superior performance at zero bias, with a high responsivity of 85.56 A·W^-1, a large detectivity of 1.80 × 10¹² Jones, and rapid photoresponse times (τ_rise = 8.15 μs, τ_decay = 21.32 μs). By incorporating the monocrystalline heterojunction film within a pixelated array architecture, real-time imaging with high-contrast is achieved. This work offers a comprehensive method for fabricating high-quality perovskite monocrystalline heterojunction films for self-powered photodetectors.