Tunable excitation-dependent-fluorescence of carbon dots: Fingerprint curves for super anti-counterfeiting

A novel concept of anti-counterfeiting is proposed, based on the special properties of excitation-dependent-fluorescence (EDF) and emission-dependent-excitation (EDE) of carbon dots (CDs) in polymer matrix . EDF and EDE behaviors can be controlled by adjusting the concentration of CDs or changing species of CDs and their corresponding polymer matrix. Meanwhile, multi-emission in EDF spectrum is observed, which is helpful to identification. Particularly, the curves in EDF or EDE spectrum as unique and sophisticated as human fingerprints are highly difficult to replicate, which promise practical applications of CDs in the field of anti-counterfeiting.