Preparation method of ultrathin bismuth selenide binary compound nanosheets

The invention discloses a preparation method of ultrathin bismuth selenide binary compound nanosheets, which comprises the following steps: adding 300ml of ethylene glycol into a three-neck flask, and fixing the three-neck flask onto a heating jacket by using a mechanical stirring device; adding 1-3 millimole of ethylenediamine tetraacetic acid into the solution, and dissolving by stirring; adding bismuth chloride with equal molar weight to the ethylenediamine tetraacetic acid, and dissolving by stirring; adding 0.1-0.5 mol/L NaOH, and dissolving by stirring; adding selenium oxide powder into the solution according to the BiCl2:SeO2 ratio of 2:3, and dissolving by stirring; heating to 120-190 DEG C, and keeping the temperature for 0.5-8 hours; and cooling to room temperature, carrying out vacuum filtration, and drying at 120 DEG C. The invention is simple to operate, easy to implement and suitable for mass production. The bismuth selenide synthesized by the method disclosed by the invention has the advantages of thin laminae, favorable crystallinity and uniform nanosheet dimension. When being used as a topological insulator material, the ultrathin bismuth selenide binary compound nanosheets can effectively lower the time reversal symmetrical scattering and further enhance the thermoelectric properties of the material, thereby having wide application prospects in the fields of thermoelectric devices and thermoelectric refrigeration.