Scalable Synthesis of Exfoliated Organometal Halide Perovskite Nanocrystals by Ligand-Assisted Ball Milling

Organometal halide perovskite materials have attracted much attention in the photovoltaic and light emitting devices due to the compositional flexibility with ABX₃ formula (A is an organic amine cation; B is a metal ion; X is a halogen atom). Recently, several approaches have been proposed to synthesize organometal halide perovskite nanocrystals (NCs) with a size-tunability of their bandgaps. However, despite successful synthetic methods of the perovskite NCs based on the precipitation of precursors in a poor solvent, a high-yield production of perovskite NCs still remains a key challenge. In this work, we show a new scalable method for exfoliated perovskite NCs by a ligand-assisted ball-milling process that combines chemical and mechanical exfoliating process. In particular, when the ligands such as octylamine and stearylamine were employed during ball-milling, the size of perovskite NCs was significantly decreased, and their photoluminescence quantum yield (PLQY) was increased, compared to the case without ligands. Moreover, it also exhibits compositional bandgap engineering that can broaden its optoelectronic applications.