In Situ Green Synthesis of Ni-Doped CsPbBr3@SiO2 Composites with Superior Stability for Fabrication of White Light-Emitting Diodes

摘要

All-inorganic perovskite nanocrystals(PNCs)have drawn enormous attention recently for their excellent optoelectronic properties.However,the poor stability to polar solvents and ultraviolet(UV)light,and the undesirable ions exchange reactions hinder their practical applications tremendously.Moreover,organic solvents and ligands with long chains are indispensable for the preparation of PNCs in most synthetic protocols,which are harmful and expensive.Herein,we have proposed an alternative in situ method to prepare Ni-doped CsPbBr3 NCs by using nontoxic water or ethanol as solvents,nickel bromide as the bromide source.Moreover,the acid-base organic ligands system such as oleylamine and oleic acid were substituted by economical ammonium hydroxide and acetic acid.Then the composites of SiO2 and PNCs,namely,SiO2@PNCs and PNCs@MSN@SiO2(MSN is mesoporous silicon nanoparticles),are prepared in aqueous system efficiently.Especially,PNCs@MSN@SiO2 exhibits excellent luminescent properties and superior stability against water,UV light irradiation and ions exchange reactions.Finally,by using the green-emitted PNCs@MSN@SiO2,and red-emitted CsPbBrI2 phosphors,a warm white light-emitting diodes(WLED)device can be fabricated,which shows potential applications of backlit displays with a wide color gamut of National Television System Committee(NTSC)value of 110% and ITU-R Recommendation B.T.2020(Rec.2020)of 87%.This work may provide a new eco-friendly strategy to prepare high performance PNCs and their composites.