Two-Dimensional Ruddlesden–Popper Perovskite Cs₂PbI₂Cl₂ Nanostructures for Self-Powered Visible–Blind Ultraviolet Photodetectors

All-inorganic two-dimensional Ruddlesden–Popper perovskite Cs 2 PbI 2 Cl 2 nanostructures with excellent thermal stability, tunability, and carrier mobility have great potential to be utilized as functional layers in visible–blind ultraviolet photodetectors. In order to achieve efficient devices, we prepare herein Cs 2 PbI 2 Cl 2 nanostructures using a two-step dipping method and reveal the growth process of the nanostructures from nanowires to films. The morphologies of the intermediate nanosheets and nanosheet/film structures are characterized to investigate their microstructural characteristics and crystallization processes. Furthermore, typical Cs 2 PbI 2 Cl 2 nanostructures are utilized to construct low cost, simple-structured, self-powered photodetectors. The self-powered champion device based on a Cs 2 PbI 2 Cl 2 nanosheet/film nanostructure exhibits a peak responsivity of 35.01 mA/W, a specific detectivity of 2.45 × 10 12 Jones, and a short response time of 80 μs, together with exceptional operational stability in ambient air. The favorable electronic performance is strongly related to the suppressed carrier recombination and enhanced built-in potential.