Laser-Induced Synthesis of Hexagonal Cesium–Lead–Bromine Perovskite and Cubic Cesium–Bromine Nanocrystals for Light-Emitting Diodes

Shape-controlled nanomaterials are essential to diverse applications in terms of physics, chemistry, and biology due to their unique properties. However, the thermodynamic limitation of matter inherently prevents the variation and development of shape manipulation of nanomaterials based on traditional chemical methods. In this work, we present a strategy of laser-induced transient nonequilibrium thermodynamic processes for colloidal perovskite nanocrystals (NCs) synthesis in the liquid phase. Benefitting from the local high temperature and pressure induced by the pulsed laser, we successfully achieved monodispersed hexagonal CsPbBr3 NCs and cubic CsBr NCs. The band structure of hexagonal CsPbBr3 NCs is tunable by controlling the irradiation time and concentration of the precursor, showing varied photoluminescence emission in the range of 452–530 nm. The cyan hexagonal CsPbBr3 NCs (502 nm) show near-unity photoluminescence quantum yields of over 90%. Finally, the green perovskite light-emitting diodes (LEDs) based on the hexagonal CsPbBr3 NCs were fabricated. This work provides a method for synthesizing efficient noncubic CsPbBr3 NCs and demonstrates its promising application in LEDs.