Facile and fast synthesis of N, S-codoped graphene quantum dots for durable luminescent labels: Application and validation through artificial intelligence

This study presents the synthesis of blue-emissive nitrogen and sulfur co-doped graphene quantum dots (N, S-GQD_blue) via a rapid microwave-assisted pyrolysis method. To overcome the challenge of aggregation-caused quenching (ACQ), which limits the application of quantum dots in solid-state devices, we propose embedding the N, S-GQDblue into polymer matrices. X-ray photoelectron spectroscopy (XPS) confirmed the presence of amine active sites, enabling crosslinking with epoxy monomers. Incorporating N, S-GQD_blue into an epoxy matrix effectively mitigated ACQ effects while maintaining photoluminescence (PL) intensity, with over 86 % of PL retained after two months of storage. This study demonstrates potential applications in anti-forgery measures through stealth patterning and printing. Additionally, a Python-based image processing script was developed to authenticate printed patterns, achieving 100 % structural similarity and verifying emission wavelength accuracy. These findings advance the development of luminescent labels as foundational security elements, with promising applications in anti-counterfeiting, security devices, and optical sensing.