Near-infrared silver sulphide quantum dot as well as preparation method and application thereof

The present invention discloses a near-infrared silver sulfide quantum dots, their preparation and use. The silver sulfide quantum dot having a monoclinic structure, which is 8nm or less in diameter, and its surface may be modified thiol group connecting a hydrophilic group of the hydrophilic agent. The preparation method comprises the steps of: containing a silver source and a long-chain thiol mixing of the reaction system in the reaction fully closed environment; the polar solvent is added after mixing of the reaction system was cooled, centrifuged and washed to obtain a near infrared hydrophobic silver sulfide quantum point; hydrophobic quantum dots near infrared silver sulfide and mercapto group-containing hydrophilic agent is sufficiently mixed in an organic solvent, the reaction mixture was centrifuged and washed, to obtain the near-infrared biocompatible silver sulfide quantum dot. Fluorescence quantum yield point of the present invention, good fluorescence stability, good biocompatibility, uniform size, can be used for imaging biological tissue, and mild preparation conditions, simple operation, short cycle, reproducible, easy to control .