The invention discloses a near-
infrared silver sulphide
quantum dot as well as a preparation method and application thereof. The silver sulphide
quantum dot has a monoclinic phase structure, the particle
diameter of the silver sulphide
quantum dot is below 8nm, and the surface of the silver sulphide
quantum dot can be connected and modified with a hydrophilic group of hydrophilic
reagent containing sulfydryl. The preparation method comprises the following steps: fully reacting a mixed
reaction system containing silver source and long-chain mercaptan in a sealed environment; cooling the mixed
reaction system, and then adding a polar
solvent; carrying out
centrifugation and wshing to obtain a hydrophobic near-
infrared silver sulphide
quantum dot; fully mixing the hydrophobic near-
infrared silver sulphide
quantum dot and hydrophilic
reagent containing sulfydryl in
organic solvent to react; and carrying out
centrifugation and washing the reacting mixture to obtain the
biocompatibility near-infrared silver sulphide quantum dot. The quantum dot disclosed by the invention has the advantages of high
fluorescence yield, good
fluorescence stability, good
biocompatibility and even size, and can be used for
biological tissue imaging; and the preparation technology has moderate condition, short period and good
repeatability, is simple to operate and is easy to control.