Preparation method of indium phosphide quantum dots with narrow emission spectrum

The invention discloses a preparation method of indium phosphide quantum dots with a narrow emission spectrum. The preparation method comprises the following steps: firstly, preparing a transparent and clear indium precursor solution; adding a phosphorus source at a first temperature, and reacting at a constant temperature to obtain an indium phosphide core with a uniform size; coating the sulfur-selenium-zinc alloy inner shell layer by adopting a gradient variable-temperature solution growth method at a second temperature; and then raising the temperature to a third temperature, and synthesizing a zinc sulfide shell layer at a constant temperature to form the InP/ZnSeS/ZnS indium phosphide multi-shell quantum dot. According to the method disclosed by the invention, the inner shell layer is coated through gradient heating, so that the defects between the core and the shell are reduced, the maximum quantum yield of the prepared indium phosphide quantum dot exceeds 90%, the half-peak width is about 36 nm, and t