The more the merrier: optimizing monomer concentration for supersaturation controlled synthesis of stable ultra-small CsPbBr 3 nanocrystals for blue emission.

Synthesis of strongly quantum confined and emissive CsPbBr 3 perovskite nanocrystals with sizes <4 nm has proven challenging owing to fast nucleation and rapid growth. In this work, ultra-small blue-emitting (∼461 nm) CsPbBr 3 nanocrystals with an average particle size of 3.2 nm are synthesized via a high-temperature (170 °C) colloidal approach by controlling the supersaturation reaction conditions. Our approach yielded stable nanocrystals with uniform size, shape, and excellent color purity, making them promising for blue light emitting diode (LED) applications.