Method for preparing fluorescent carbon quantum dots by laser irradiation

The invention discloses a method for preparing fluorescent carbon quantum dots by laser irradiation. The method is characterized in that one of benzene, substituted benzene and a compound containing multiple benzene rings is used as a carbon source; a liquid-state carbon source or a carbon source solution obtained by dissolving a solid-state carbon source into ethanol is irradiated for 1-120 minutes through ultraviolet light of which the wavelength is within 380nm to obtain the fluorescent carbon quantum dots. The carbon source and the solution thereof used by the method disclosed by the invention are simple, the selection of the carbon source is diverse; the laser power and the irradiation time adopted in the preparation process are good in controllability, the preparation process can be carried out at room temperature, the particle diameter of the obtained carbon quantum dots is 2-7nm, and the carbon quantum dots have a regular graphite structure; results show that the carbon quantum dots prepared by the method have photoluminescence fluorescence property without surface modification.