Ultrabright\nand Efficient Green Perovskite Light-Emitting\nDiodes Enabled by Well-Crystallized Dense CsPbBr₃ Nanocubes

Abstract

Perovskite light-emitting diodes (PeLEDs) are promising\nfor next-generation\nhigh-definition displays. One of the keys to achieving high performance\nPeLEDs lies in how to fabricate crystalline and dense perovskite films.\nHowever, there exist challenges to directly grow well-crystallized\nCsPbBr₃ nanocrystal thin films on transport layers due\nto low solubility in solvents and fast precipitation of all-inorganic\nCsPbBr₃, and the corresponding bright, efficient, and stable\ngreen PeLEDs have rarely been reported. Herein, we report an efficient\nstrategy to prepare well-crystallized and dense CsPbBr₃ nanocubes for ultrabright and efficient green PeLEDs. We introduce\nsulfobetaine zwitterion as crystallization control agent and strontium\nfluoride nanocrystals as nucleation seeds to grow high-quality CsPbBr₃ nanocube films. Eventually, the CsPbBr₃ films\nenable green PeLEDs with a maximum luminance of 162 767 cd\nm^–2 and a champion external quantum efficiency of\n21.3% along with a narrow spectral line width of ∼14.7 nm,\nrepresenting state-of-the-art performances in green PeLEDs.