Toward tunable morphology and improved photostability in CsPbBr₃ perovskite single microcrystals

Abstract All-inorganic metal halide perovskites exhibit excellent morphology-dependent photophysical properties. Thus, detailed knowledge of photophysical behavior and morphological dependence of CsPbBr ₃ crystals is crucial for device engineering. However, the inability to directly control the morphology of CsPbBr ₃ crystals arises from a limited understanding of their crystallization mechanism. Herein, we varied the preparation parameters to investigate the perovskite growth mechanism and the impact of these parameters on the size and shape of CsPbBr ₃ single crystals. By optimizing the solution processing, the shape was tuned from the typical cubic microcrystals to more irregular ones. We have shown that three main factors favor the growth and formation of CsPbBr ₃ microcubes, namely precursor concentration, temperature, and the solvent used. The crystal size and density can be tuned by adjusting the precursor concentration, heating temperature, heating time, and drop volume. The obtained crystals were of high quality and exhibited a strong photoluminescence at room temperature. This work not only introduces a distinct new morphology within the CsPbBr ₃ microcrystals family but also provides a fundamental understanding of the growth mechanism of these newly emerging functional materials.