Chiroptical Nanocellulose Bio‐Labels for Independent Multi‐Channel Optical Encryption

Abstract

AbstractAdvanced multiplexing optical labels with multiple information channels provide a powerful strategy for large‐capacity and high‐security information encryption. However, current optical labels face challenges of difficulty to realize independent multi‐channel encryption, cumbersome design, and environmental pollution. Herein, multiplexing chiroptical bio‐labels integrating with multiple optical elements, including structural color, photoluminescence (PL), circular polarized light activity, humidity‐responsible color, and micro/nano physical patterns, are constructed in complex design based on host‐guest self‐assembly of cellulose nanocrystals and bio‐gold nanoclusters. The thin nanocellulose labels exhibit tunable circular polarized structural color crossover the entire visible wavelength and circularly polarized PL with the highest‐recorded dissymmetry factor up to 1.05 due to the well‐ordered chiral organization of templated gold nanoclusters. Most importantly, these elements can independently encode customized anti‐counterfeiting information to achieve five independent channels of high‐level anti‐counterfeiting, which are rarely achieved in traditional materials and design counterparts. Considering the exceptional seamless integration of five independent encryption channels and the recyclable features of labels, the bio‐labels have great potential for the next generation anti‐counterfeiting materials technology.