Ligand-assisted reprecipitation synthesis of highly luminescent and stable CsPbBr3@SiO2 nanoparticles with formation kinetics analysis

Abstract

Cesium lead bromide (CsPbBr3) perovskite nanocrystals are becoming a popular alternative to chalcogenide quantum dots because of their bright green fluorescence and high color purity. However, owing to the poor stability caused by their highly ionic nature and the dynamic binding of long-chain capping ligands, their practical applications are limited. Although (3-aminopropyl)triethoxysilane (APTES) is a frequently used insulating material for wrapping CsPbBr3 nanocrystals, it often causes surface etching. To address this issue, we introduced oleic acid into the anti-solvent toluene to inhibit the etching effect of APTES using a modified room-temperature ligand-assisted reprecipitation process. We utilized in situ time-dependent photoluminescence measurements to study the formation kinetics of CsPbBr3 nanocrystals and determine the optimal ligands ratio. This innovative approach enables precise control over CsPbBr3@SiO2 nanoparticles synthesis, yielding uniformly shaped nanocrystals with a silica shell, a consistent size around 10.17 ± 1.6 nm, and enhanced photoluminescence quantum yields ranging from 90% and 100%. The photoluminescence lifetimes of our CsPbBr3@SiO2 nanoparticles were significantly prolonged owing to a reduction in non-radiative recombination. This boosts their stability in thermal and polar solvent environments, making them superior candidates for use in photonic devices.