Morphology‐Controllable Perovskite‐Like RbCu₂Br₃ Single Crystals with Strong Photoelectronic Anisotropy for UV Detection

Abstract The carrier transport characteristics of grain boundary‐free, high‐purity metal halide single crystals make them ideal materials for photodetectors. However, the relationship between photoelectric properties and crystal morphology as well as electronic structure is not sufficiently explored. In this work, RbCu₂Br₃ single crystals with high quality and multiple morphologies are successfully prepared for the first time. Based on angle‐resolved polarized Raman spectroscopy and polarized photoluminescence, the anisotropy of the 1D atomic chain structure of these crystals is identified. Besides, according to the calculation of partial charge density (PCD), electron localization function (ELF), and carrier mobility related to deformation potential theory (DPT), it is found that RbCu₂Br₃ single crystals have formed a transport path located in [CuBr₄] tetrahedral double chain from 1D electronic structure. It is also explored how the factors including electronic constraints, effective mass, mechanical properties, and deformation potential affect the mobility of crystal plane. Moreover, the device constructed on crystal {100} planes has shown great potential for UV detection. This work not only provides a theoretical basis for the performance regulation of RbCu₂Br₃ single crystals in experiments but also offers scientific guidance for the growth of single crystal materials with an asymmetric structure and for the application of anisotropy‐related optoelectronics.