Inorganic perovskite CsPbX₃ （X=Cl， Br， I） nanocrystals （PNCs） have the advantages of high luminous efficiency and adjustable emission wavelength， but their poor stability limits practical applications. This study employs chlorine-containing ligands for post-treatment to synthesize CsPb（Br/Cl）₃ PNCs with tunable emission colors and investigates their luminescent properties and stability. The introduced Cl⁻ ions exchange with Br⁻ in CsPbBr₃ PNCs and passivate surface defects. By adjusting the concentration of the chlorine-containing ligands， the emission of CsPb（Br/Cl）₃ PNCs can be tuned from green to blue light. Notably， cyan-emitting CsPb（Br/Cl）₃ PNCs maintain high luminescence intensity after being immersed in water for 15 days， with stable emission peak position and full width at half maximum （FWHM）. Their photoluminescence quantum yield （PLQY） improves compared to untreated CsPbBr₃ PNCs. Finally， a cyan-light-emitting diode （LED） using CsPb（Br/Cl）₃ PNCs with a 370 nm chip was fabricated， achieving CIE chromaticity coordinates of （0.116， 0.264）， showing potential to supplement the cyan light in white LEDs.

perovskite nanocrystals;halogenated ligand;stability;light emitting diode