Dual-modal information storage and anti-counterfeiting material, and its preparation method

An information encryption storage and anti-counterfeiting method based on a dual-modal information storage and anti-counterfeiting material prepared by a preparation method, the information encryption storage and anti-counterfeiting method comprising:

• by adopting a digital light processing (DLP) ultraviolet (UV) projector or a photomask-UV lithography technique, applying a 300 nm-500 nm light source to irradiate patterned information on the dual-modal information storage and anti-counterfeiting material, wherein an irradiation power of the 300 nm-500 nm light source is 0.5 W-5 W, which realizes a storage of the patterned information by allowing partial fluorescence quenching and causing a brown-black photocorrosion discoloration to occur in an irradiation area;
• realizing an encrypted fluorescent patterned information by turning off the 300 nm-500 nm light source and allowing a discoloration area of the irradiation area to be gradually restored under aerobic environment until the discoloration area is invisible under visible light;
• and
• achieving an anti-counterfeiting verification by conducting another irradiation on the dual-modal information storage and anti-counterfeiting material with a UV light having a power of less than 0.5W to reveal the encrypted fluorescent patterned information;
• wherein the preparation method comprises the following steps:
• (1) synthesizing cadmium sulfide quantum dots (CdS QDs) modified by thiol ligand with controllable photocorrosion function in an aqueous phase comprising:
• preparing a CdCl2 aqueous solution, continuously stirring the CdCl2 aqueous solution and adding the thiol ligand to produce precipitate;
• adding HCl or NaOH solution dropwise until a pH of the CdCl2 aqueous solution including the thiol ligand reaches 7;
• adding a Na2S aqueous solution under stirring;
• adding ethanol for precipitating;
• and
• obtaining CdS QDs by centrifugation and washing;
• wherein a molar ratio of cadmium chloride to the thiol ligand is between 1:1-1:2;
• and
• (2) preparing a hydrogel ink containing the CdS QDs synthesized in step (1), and applying the hydrogel ink onto a substrate through spray coating or dip coating to obtain the dual-modal information storage and anti-counterfeiting material.