The invention discloses a method for preparing mononuclear AgInS2
quantum dots, comprising the following steps of: (1) adding AgNO3, InCl3,
oleic acid, dodecyl mercaptan and
solvent octadecene in a reaction container, to obtain an Ag and In precursor mixed liquor; (2) adding
sulfur powder into
oleylamine, and heating until the
sulfur powder is fully dissolved, to obtain an S precursor solution; (3) under protection of
argon, heating the Ag and In precursor mixed liquor from
room temperature to 50-80 DEG C, and maintaining for 10-60min, in order to discharging air; and then raising temperature to 100-120 DEG C, maintaining for 1-5min, and injecting the S solution, wherein a mol ratio of Ag to S is 1:2, and reaction time is 5-90min; (4) sampling, and dissolving a sample into
hexane, to obtain a AgInS2
quantum dot solution; and (5) adding waterless
ethanol into the AgInS2
quantum dot solution obtained in the step (4), and centrifugally separating to obtain the mononuclear AgInS2 quantum dots. The method of the invention further raises fluorescent
quantum yield of the mononuclear AgInS2 quantum dots prepared by a thermal injection method, in order to reach practical application requirement.