Next‐generation anti‐counterfeit security using carbon nanodots: Tunable luminescence and sustainable ink design—A review

Counterfeiting technologies have advanced rapidly, outpacing conventional safeguards such as barcodes and holograms, and creating demand for adaptable and sustainable alternatives. Carbon nanodots (CNDs) are emerging as promising next‐generation anti‐counterfeiting materials due to their tunable optical properties and compatibility with printable inks. Their luminescence arises from multiple mechanistic pathways, including fluorescence (FL), room‐temperature phosphorescence (RTP), and thermally activated delayed fluorescence (TADF), which can be combined into multi‐tier authentication strategies. These multimodal emissions improve resistance to cloning and enable field validation using simple portable devices. Beyond optical features, the printability of CND‐based inks depends on their rheological parameters, such as viscosity, surface tension, and particle‐to‐nozzle size ratio, which must be carefully tailored for different printing methods (inkjet, screen, laser, roll‐to‐roll). Binder systems (e.g., PVA, PEG, acrylics) and solvent selection further influence ink stability, curing, adhesion, and durability against abrasion, solvents, and light exposure. This review highlights how the synthesis, doping, and passivation of CNDs govern structure–property–function relationships and how these translate into practical ink formulations and printing technologies. By integrating materials science, ink rheology, and engineering considerations, CNDs can be positioned as scalable and eco‐friendly candidates for next‐generation anti‐counterfeiting security platforms.