The invention relates to the technical field of developing materials, and discloses a preparation method and application of a luminescent nanocluster, the preparation method comprises the following steps: step 1, dissolving a
metal precursor in
methanol to prepare a
metal precursor solution, the
metal precursor being selected from
silver nitrate,
copper nitrate or a combination thereof; step 2, adding 4, 6-dimethyl-2-mercaptopyrimidine into the metal precursor solution, and carrying out a stirring reaction to form a complex; 3, adding
sodium hydroxide into the reaction mixture, and continuously stirring until a
luminescence phenomenon occurs; step 4, carrying out centrifugal treatment on the reacted solution, and separating to obtain an upper solution and a lower precipitate; step 5, respectively collecting the upper solution and the lower precipitate redissolved by
methanol, and standing; step 6, obtaining a high-
luminescence nanocluster
crystal in a natural volatilization or standing and airing mode; the absolute luminous
quantum efficiency of the material prepared by the invention is 60% or above, and some absolute luminous
quantum efficiencies are even close to 100%; the light-emitting
wavelength can be adjusted from yellow-green to red, the
latent fingerprint showing precision is extremely high, the third-level characteristics of fingerprints can be clearly shown, the advantages of being simple in synthesis process, low in cost, small in
pollution and the like are achieved, and wide application prospects are achieved in the technical field of new-generation
fingerprint detection.