Method for preparing water-soluble fluorescent ZnSe/ZnS core-shell quantum dots

The invention belongs to the technical field of nano-material preparation techniques and biological analysis detection, and in particular relates to a method for preparing water-soluble fluorescent ZnSe/ZnS core-shell quantum dots. The method comprises: adopting a coprecipitation method and taking thioglycollic acid as surfactant to synthesize ZnSe quantum dots in aqueous solution; adding excessive Zn precursor solution to reaction solution dropwise so as to enrich a large number of Zn2+ ions on the surface of quantum dots; adding (NH4)2S solution dropwise to the solution at a certain rate and controlling temperature so as to ensure that S2- subsequently added and Zn2+ ions enriched on the surface are covalently bound to form a ZnS shell; and avoiding the uniform nucleation of ZnS by adjusting experimental parameters. The core-shell quantum dots prepared by the method are compact in core-shell structure, and the quantum dots uniform in size distribution (3 to 6 nanometers) can be obtained without further size separation.