Peacock‐Inspired Janus Structural Color Materials for Multi‐Level Encryption and Anti‐Counterfeiting

nanoparticles on the PC side is highly ordered, producing a bright iridescent color. In contrast, the order degree of nanoparticles on the PG side is low, resulting in a muted color with less angular dependence. Adjusting the molecular weight of PEG can modulate the driving force of the assembly, allowing control over the spatial position of the PC and PG domain within the film. The Janus structure also can control the fluorescence intensity of organic dyes in the film to produce diverse optical signals with great potential for multi-level information encryption and anti-counterfeiting.