Shape Tailoring of Iodine‐Based Cesium Lead Halide Perovskite Nanocrystals in Hot‐Injection Methods

Abstract All‐inorganic lead‐halide perovskite nanocrystals continue to attract the attention of the scientific community due to their optical potential. In this work, we demonstrate that synthetic approaches based on the modulation of the ligand‐to‐metal ratio in hot‐injection methods can provide direct access to a variety of colloidal nanocrystal morphologies without resorting to post‐synthetic transformations. The shape tailoring observed for iodine‐based perovskite nanocrystals suggests that nanowires can evolve through the oriented attachment of nanocubes in the presence of high ligand‐to‐metal ratios. Conversely, mixed‐halide perovskite nanoplatelets are generated in low‐surfactant regimes, due to the peculiar reactivity of halo‐plumbate species generated before cesium injection, which favors an anisotropic growth of the nanoparticles. These results contribute to deepen the knowledge on the shape evolution of perovskite nanoparticles, thus opening the way to the development of new synthetic approaches.