In this work, we developed inverse opal photonic crystals (IOPCs) for real-time identifiable labels by tuning the structure color and chemical color under ultraviolet (UV) light and near-infrared (NIR) light. We prepared IOPCs by etching a silica photonic crystal template in thermosensitive hydrogel added to 2,2-diphenyl-2H-naphtho [1,2-b] pyran-6-carbaldehyde (NP). In this way, the transparent hydrogel turned red under UV light due to the photochromic naphthopyran. Meanwhile, the green structure color of IOPCs was superimposed with the red chemical color of the hydrogel, so that IOPCs with naphthopyran (IOPCs/NP) appeared yellow. When irradiated by NIR light, the structure color of IOPCs turned blue from green due to the volume contraction of the thermosensitive hydrogel. When irradiated by UV and NIR light simultaneously, the blue structure color of IOPCs was superimposed with the red chemical color of the hydrogel, and the IOPCs/NP would finally appear purple. Thus, we realized the real-time controllable IOPCs by two light sources. Based on this, we designed a series of identifiable labels with multiple colors under UV and NIR light, which expanded the application of information anticounterfeiting and identification.
Based on etched PS sphere arrays, the different growths of Ag nanoparticles with tunable LSPR are designed when SiO2-25 nm/Ag-30 nm/SiO2-100 nm sandwich nanocavity structures are annealed at 500 °C, including the hexagonal silver nanoparticle rings, circular silver nanoparticle rings, and aggregated silver nanoparticles. The uniformity of particle size and regularity of position generate enhanced electromagnetic field and good surface-enhanced Raman spectroscopy signals as confirmed by UV–vis observation and finite difference time domain method simulation. The developed nanostructures are effectively used as stable, nonreproducible, and markable anti-counterfeiting signs.
危险品化学品经营许可证（带存储）