Se powder as precursor without solubilization for Mn-doped ZnSe QDs: Fast synthesis and analytical characterization

As a typical doped quantum dots, Mn doped ZnSe quantum dots (Mn:ZnSe QDs) is widely used for bio-imaging applications due to its excellent optical properties and low toxicity. However, it is difficult to dissolve and easy to oxidize selenium powder. In order to solve this problem, a heterogeneous Se powder instead of homogeneous Se solution was used here as anionic precursor for synthesis of Mn doped ZnSe QDs based on “nucleation-doping” method. Selenium powder was directly injected into manganese precursors under high temperature, then selenium powder slowly but constantly dissolved and promoted the formation of MnSe nanocrystals with the balance of chemical reaction, which would quickly generate Mn-doped ZnSe QDs with the addition of zinc ion precursor. Compared with homogeneous Se for synthesis of Mn doped ZnSe QDs, this method can achieve fast synthesis of high quality QDs that can also be water-soluble through ligand change with mercaptopropionic acid (MPA). The obtained product was carefully charaterized, and trace impurities was analytically determined.