Femtosecond laser-patterned microfluidic surfaces with spreading carbon QDs toward dynamic information encryption

Abstract

Traditional static optical anti-counterfeiting relies on fixed luminescent patterns or a single optical response, making it susceptible to copying and counterfeiting; moreover, its mode of information presentation is singular, making it difficult to meet the demands of information encryption with high concealment and high security. To address this issue, this paper proposes a dynamic information encryption strategy based on the dual-dimensional synergy of “spatial patterning–temporal afterglow.” Superhydrophilic micropatterned regions were constructed on a stainless-steel surface by femtosecond laser direct writing, and, with the aid of wettability differences and capillary driving, rapid spreading and high-resolution confined deposition of the carbon quantum dot (QD) precursor solution within the predefined regions were achieved. After high-temperature dehydration curing and secondary thermal treatment, carbon QD afterglow patterns with stable performance were obtained, and programmable tuning of the afterglow lifetime within 2.5 s could be achieved by regulating the precursor concentration. Based on the spatially confined patterns and temporal decay differences, a dynamic encryption mode of “instantaneous appearance of misleading information–delayed decoding of real information” was further established. This strategy integrates femtosecond laser microstructuring with programmable afterglow materials, realizing dual protection of information in both spatial and temporal dimensions, and providing a new design concept for dynamic anti-counterfeiting and high-security information encryption.