Lead‐halide‐based perovskite single crystals have attracted wide attention due to their excellent optical characteristics, photoelectric performance, and designable structures. 2D sheet‐like single‐crystal perovskite materials have several attractive characteristics, including larger exposed facets, adjustable thickness, good light absorption/transparency, and so on. However, single‐crystal perovskite sheets with a thinner thickness (<10 μm) are hard to obtain by conventional mechanical cutting due to the fragility of perovskite single crystals. Herein, the recent progress in research on 2D perovskite single crystals from macro‐ to microscale is reviewed. Crystal growth methods are classified into six strategies, including space‐limit method, surface‐tension method, top‐down method, spin‐coating method, solution‐phase method, and vapor‐phase method. Subsequently, the properties of 2D perovskite single crystals are further highlighted, such as optical properties, crystal defects, carrier transport properties, detection capability, and stability. Moreover, their applications in single‐crystal photodetectors are summarized. Finally, the summary and perspective on 2D perovskite single crystals are also briefly addressed.

Due to their many varieties of excellent optoelectric properties, perovskites have attracted large numbers of researchers in the past few years. For the hybrid perovskites, a long diffusion length, long carrier lifetime, and high μτ product are particularly noticeable. However, some disadvantages, including high toxicity and instability, restrict their further large-scale application. By contrast, all-inorganic perovskites not only have remarkable optoelectric properties but also feature high structure stability due to the lack of organic compositions. Benefiting from these, all-inorganic perovskites have been extensively explored and studied. Compared with the thin film type, all-inorganic perovskite single crystals (PSCs) with fewer grain boundaries and crystalline defects have better optoelectric properties. Nevertheless, it is important to note that only a few reports to date have presented a summary of all-inorganic PSCs. In this review, we firstly make a summary and propose a classification method according to the crystal structure. Then, based on the structure classification, we introduce several representative materials and focus on their corresponding growth methods. Finally, applications for detectors of all-inorganic PSCs are listed and summarized. At the end of the review, based on the current research situation and trends, some perspectives and advice are proposed.