Water-Based Route to Synthesis of High-Quality UV-Blue Photoluminescing ZnSe/ZnS Core/Shell Quantum Dots and their Physicochemical Characterization

Abstract

Epitaxially overgrowing a semiconductor material with higher bandgap around the QDs has proven to be a crucial approach for improving the PL efficiency and stability of nanocrystals. In this paper, a ZnS shell was deposited around ZnSe nanocrystal cores via a noninjection approach in aqueous media. The deposition procedure conducted at 100°C in a reaction flask in the presence of the shell precursor compounds, together with the crude ZnSe nanocrystal cores and the thiol ligand glutathione. The influences of various experimental variables, including the reaction time, amount of thiourea, as well as pH value, on the growth rate and luminescent properties of the obtained core/shell nanocrystals have been systematically investigated. In comparison with the original ZnSe nanocrystals, the PL efficiency of the obtained ZnSe/ZnS core/shell nanostructures can be improved significantly with a QY up to 62.8%.