Preparation And Response Behavior Of Photonic Crystal With High Refractive Index For Information Coding

In optical information coding functional materials,Photonic crystals form Photonic Band gaps that reflect specific wavelengths of electromagnetic waves through an ordered arrangement of materials with different refractive indexes.By combining photonic crystals with responsive materials,the response can be generated by stimulating the external environment and then the lattice parameters can be changed to achieve the purpose of photonic crystals to regulate light in different bands.In this paper,cadmium sulfide photonic crystals with high refractive index were designed and prepared,and they were combined with responsive materials to prepare high refractive index photonic crystals through Angle dependence and fluorescence regulation of upconversion nanoparticles.Their response mechanism was studied,and their application in information coding was explored.The main research contents include:1.Multi-angle patterned photonic crystal films based on CdS and Si O₂colloidal particlesA multi-angle structured photonic crystal film containing two kinds of photonic crystals was prepared by combining CdS and Si O₂ colloidal particles with hydrogel through self-assembly of colloidal particles and uv curing.CdS has a higher refractive index,while sio2 has a lower refractive index,so the two kinds of photonic crystals have obvious angle-dependent difference.Based on the difference of Angle dependence,a multi-angle pattern is designed to realize the function of information storage,display,and anti-peeping through the change of incident light angle.colors were prepared by using the difference between the regulation of silicon dioxide and cadmium sulfide on upconversion fluorescence.The photonic crystal lattice,anti-counterfeiting label and patterned film with information encoding function are designed by using this property.2.Composite photonic crystals based on CdS and Si O₂ particles and upconversion fluorescence regulationThe photonic crystal/upconversion composites were prepared by combining upconversion nanoparticle with CdS and Si O₂ colloidal particles under capillary force by self-assembly of colloidal particles.Due to the high refractive index of CdS,the photonic crystal formed by CdS has a special regulation effect on up-conversion fluorescence,which can effectively enhance the red band of fluorescence and turn the original green fluorescence into yellow.In this work,the regulation of cadmium sulfide on upconversion fluorescence was studied,and the photon-crystal/upconversion nanoparticle films with different fluorescenceTo sum up,this paper studies CdS photonic crystals with high refractive index and combines them with responsive materials.This photonic crystal material has wide application value in display devices,anti-counterfeiting,information encryption and other fields.