Preparation method for small-size gold nano-clusters, and gold nano-clusters

The invention discloses a preparation method for small-size gold nano-clusters. According to the method, nano-scale gold atomic clusters with sizes of 0.8-1.2 nanometres and a quantum size effect can be simply and efficiently synthesised, and the gold nano-clusters have a wide application prospect in the fields of biosensing, fluorescence analysis and the like due to special physicochemical properties. The synthesis method mainly comprises the following two steps: (1) firstly, dissolving chloroaurate trihydrate (HAuCl4.3H2O) and different phosphine ligands (such as triphenylphosphine and diphenylhydroxyl phosphine) in a mixed solvent of ethanol and water, and reacting at a normal temperature to generate a product 1; and (2) adding a reducer, that is, sodium borohydride, in acetone to reduce the product 1, and finally obtaining the small-size gold atomic nano-clusters. The synthesis route disclosed by the invention has the advantages that raw materials are simple and easily available, reaction conditions are simple and practicable, and operation and control are simple.