[Abstract]

Unlike organic-inorganic hybrid perovskites, all-inorganic metal-halide perovskite nanocrystals such as CsPbX3 (X = Cl-, Br-, and I-) have attracted wide and close attention owing to their outstanding optoelectronic properties, such as broad absorption wavelengths (410-700 nm), narrow emission spectra (12-42 nm), tunable bandgaps (1.7-3 eV) as well as high excellent photoluminescence quantum efficiency (PLQE, > 90%), which have aroused a lot of studies, including light-emitting diodes (LEDs), solar cells, display and laser. In particular, perovskite nanocrystals are actively studied in LEDs because of the solution processing. Recently, perovskite LEDs have reached an external quantum efficiency (EQEs) over 20%. Although perovskite NCs are intensively studied in a variety of fields, they are required to be synthesized in a restricted condition such as in an inert gas atmosphere due to their moisture sensitivity. Herein, we synthesized perovskite NCs using the ligand-assisted reprecipitation (LARP) method, which is using differences of solvent solubility. High solubility solvents, e.g., DMF (N-dimethylformamide) inject into poor solubility solvents, e.g., toluene with vigorous stirring. Right after the injection, the supersaturation state was emerged and perovskite NCs were synthesized.