Toward Tunable Morphology and Improved Photostability in CsPbBr₃ Perovskite Single Microcrystals

All-inorganic metal halide perovskites exhibit excellent morphology-dependent pho-tophysical properties. Thus, detailed knowledge of photophysical behavior and mor-phological dependence of CsPbBr3 crystals is crucial for device engineering. However, the inability to directly control the morphology of CsPbBr3 crystals arises from a lim-ited understanding of their crystallization mechanism. Herein, we varied the prepara-tion parameters to investigate the perovskite growth mechanism and the impact of these parameters on size and shape of CsPbBr3 single crystals. By optimizing the solu-tion processing, the shape was tuned from the typical cubic microcrystals to more ir-regular ones. We have shown that three main factors favor the growth and formation of CsPbBr3 microcubes, namely high precursor concentration, high temperature and the use of DMSO solvent. The crystal size and density can be tuned by adjusting the precursor concentration, heating temperature, heating time and drop volume. The ob-tained crystals were of high quality and exhibited a strong photoluminescence at room temperature. This work not only introduces a distinct new morphology within the CsPbBr3 microcrystals family but also provides a fundamental understanding of the growth mechanism of these newly emerging functional materials.