High binding ability ligand controlled formation of CsPbX3 (X = Cl/Br, Br, I) perovskite nanocrystals with high quantum yields and enhanced stability

Abstract

CsPbX₃ NCs with both high photoluminescence quantum yields (PLQYs) and enhanced stability have been obtained by using high binding ability ligands. As a result, the CsPbI₃ NCs prepared using palmitic acid and oleylamine as ligands have high PLQY (up to 92%), and the PLQYs of CsPbX₃ perovskite NCs can be sustained for one month with a slight decrease. Impressively, the presence of palmitic acid and stearic acid can dramatically improve the chemical stability of CsPbX₃ NCs. Importantly, ¹H NMR measurements indicate that much more palmitic acid remained on the surface of CsPbX₃ NCs than oleic acid after purification using solvent, suggesting the higher binding ability of palmitic acid than oleic acid. Finally, the fabricated perovskite NCs were used as luminescent inks and phosphors of white light emitting diodes.