Bio-inspired pigment particles with dual-variation modes of structural colors and fluorescence

Colorful pigments have demonstrated values in constructing dynamic patterns for different applications. Attempts in this field tend to develop pigments with multiple modes for color variation. Herein, inspired by the color variation mechanism of chameleons, we propose a novel kind of pigments with dual color variations (PDCVs) by integrating hydrophobic carbon dots (HCDs) within photonic crystal (PhC) particles. The HCDs with blue dispersion emission and red aggregation-induced emission are generated via one-pot solvothermal treatment. The PDCVs are generated by using HCDs-tagged responsive hydrogel to replicate the nanostructure of silica nanoparticles assembled spherical PhC particles. As the dispersion/aggregation of HCDs and hydrogel lattice of the PhC are depending on their surrounding solvent, the resultant PDCVs can perform dual color variations, including fluorescence and structure color, by changing their solvent. Based on this feature, we have demonstrated that the PDCVs can be employed as elements to construct various dynamic colorful patterns with wide viewing angle and allow for eminent information encryption. There results indicate that the proposed PDCVs are promising to have practical applications in the fields of information encryption, displaying, anti-counterfeiting, and so on.