Novel aqueous synthesis methods for ZnTe/ZnSe and Mn2+-doped ZnTe/ZnSe Type-II core/shell quantum dots

Abstract

In this paper, novel approaches for the synthesis of Type-II core/shell quantum dots (ZnTe/ZnSe QDs) and Mn²⁺-doped Type-II core/shell quantum dots (Mn : ZnTe/ZnSe QDs) with mercaptopropionic acid (MPA) as stabilizer were proposed. To our knowledge, it is the first time that both core/shell and doping synthesis methods are employed together to prepare photoluminescent Type-II core/shell Mn : ZnTe/ZnSe QDs in aqueous phase. The results show that the photoluminescence (PL) character of ZnTe/ZnSe QDs significantly changed with the doping of Mn²⁺. Furthermore, the fluorescence color of the QDs ranged over an extended emitting wavelength from blue to orange. Also, an increased PL quantum yield (from 5.3% to 7%) was obtained. The effects of the experimental conditions for synthesis and the PL emission properties were investigated in detail. The simple synthetic routes and improved optical properties make these QDs excellent probes for various strategies in chemo/biosensing and bioimaging.