Synthetic development in Cd–Zn–Se quantum dots chemistry

Abstract

Despite a great number of studies devoted to the synthesis of chalcogenide quantum dots (QDs), many essential questions remain open up to date. Primarily, it is a safety of the synthesis, both in the laboratory and in the industry. Another issue is the reproducibility of QDs with desired characteristics. And, without doubt, the ability to adjust properties of the resulting QDs by the implementation of various approaches to the synthesis is significant. Here we provide a novel approach to the synthesis of ternary Cd–Zn–Se QDs (ratios Cd: Zn = 10 : 90; 25 : 75; 50 : 50; 75 : 25; 90 : 10) using disubstituted selenourea as a novel source of selenium. (Z)-1-hexyl-3-(octadec-9-enyl)selenourea was synthesized in three steps with a good yield of the final product. It opens up a simple, convenient and environmentally friendly way to the synthesis of the selected QDs. Varying the molar ratios of Cd and Zn, QDs of different composition were produced in high yields. According to the conducted research, highly photoluminescent ternary Cd–Zn–Se QDs (photoluminescent quantum yield PL QY up to 64%) are uniform, both in elemental composition and in size (3.6–5.3 nm). Moreover, the selection of given selenourea made it possible to scale the synthesis by 24 times with an increase in the amount of QDs without loss of product quality. This demonstrates the feasibility to produce such type of materials on an industrial scale.