Three-Step Solution Method to Control the Crystal Size of CH3NH3PbBr3 Perovskite for Highly Efficient Light-Emitting Diodes

A three-step solution process was reported for facile control of the crystal size of CH ₃ NH ₃ PbBr ₃ (MAPbBr ₃ ) perovskite for efficient perovskite light-emitting diodes (PeLEDs). In our process, the antisolvent completely sandwiched the perovskite precursor, inducing fast nucleation and eliminating pinhole problems. The crystal size could be greatly reduced from 5 μm to 0.3 μm (less than 1/10th of the size) using our proposed process, compared to the conventional process. The obtained proper morphology of the perovskite emitting layer led to a complete pinhole-free surface and efficient charge injection into the perovskite. Consequently, the current efficiency and maximum brightness were sharply improved up to 10.35 cd/A and 48,091 cd/m ² , respectively, which were 1.7 and 2 times higher than that of reference devices, respectively.