Multiangle Patterned Photonic Films Based on CdS and SiO₂ Nanoparticles for Bar Code Applications

This paper proposes a patterned material composed of two types of photonic crystals based on CdS and SiO2 nanoparticles. We combined the photonic crystals with poly(ethylene glycol) diacrylate (PEGDA) by nanoparticle self-assembly and UV curing and successfully formed a material containing the different photonic crystals. The material prepared contains two kinds of photonic crystals with different refractive indices, CdS and SiO2 nanoparticles, and due to the large difference in refractive indices of the two materials, the reflection wavelengths of the photonic crystals composed of the two materials also have disparities when the incident angle changes. Macroscopically, the structural colors of the two photonic crystals change with the change in incident angle. In response to this phenomenon, we designed a variety of applications based on a multiangle patterned photonic crystal film to achieve a variety of information storage functions by changing the incident angle and, through the angle change, to achieve lipstick logo, mobile phone bar code, and antipeeping keyboard applications.