One pot synthesis of thick shell blue emitting CdZnS/ZnS quantum dots with narrow emission line width

Abstract

High quality blue emitting quantum dots (QDs) are regarded as promising nanomaterials for lasers, photovoltaic cells and displays. However, few reports realize high photoluminescence quantum yield (PL QY), narrow emission band width and pure blue emitting (450∼460 nm) simultaneously. Herein we propose a facile one-step synthesis of thick shell blue emitting CdZnS/ZnS QDs. ZnS shell was overcoated on the prepared cores by directly introducing zinc oleate/S TBP solution (zinc oleate powder and S dissolved in TBP) into mixture without any purification steps and the thickness of ZnS shell was controlled by adjusting the adding amount of zinc oleate/S TBP solution. The optimal QDs with ten monolayers of ZnS shell exhibit pure blue light (∼455 nm) with narrow line width (full width half maximum, FWHM 17.2 nm) and high photoluminescent quantum yield (QY) (92%). Due to the thick ZnS shell, nonradiative recombination of the QD solids is suppressed efficiently.