Enabling Single‐Challenge Multichannel‐Response OPUFs: Adaptive Nanofilms from Aggregation‐Controlled Multicolor Carbon Dots

Optical physical unclonable functions (OPUFs) provide a powerful and advanced anti-counterfeiting solution by harnessing inherent random physical features. However, achieving a balance among multichannel unclonability, scalability, and non-destructive implementation remains a significant challenge. This study introduces a single-challenge, multichannel-response OPUFs label engineered with hierarchical disorder spanning sub-nanoscale molecular programming, nanoscale assembly amplification, and microscale optical integration. First, by precisely controlling the ratio of surface functional groups, the carbon dots are directed to form either highly aggregated or weakly aggregated states. These aggregation states spontaneously generate sub-nanoscale fractal structures with intrinsic randomness, which function as physically unclonable fingerprints. Moreover, the random assembly and printing produce irreproducible micro-nano architectures that are inherently resistant to duplication. The OPUFs validation confirms an ultrahigh theoretical encoding capacity of ≈2.04 × 10⁹⁰. A single 5 µm label generates three independent keys from bright-field, green, and red channels, exhibiting near-ideal bit uniformity and exceptionally low error rates. When demonstrated on delicate butterfly specimens, the label integrates seamlessly into protective coatings without damaging microscopic features, providing an "invisible armor" with broad applications in secure data storage and high-precision anti-counterfeiting.