Ding Longjiang's work has been accepted on JACS, Congratulations

A new covert luminescent anti-counterfeiting (AC) technology was developed by employing combinatorial chemistry and concentration-dependent stimulus-responsive luminescent patterns. Oxygen-sensitive materials are carefully tailed to be inkjet printable and to form luminescent color inks. The inks are placed in the ink tanks of a commercial ink-jet printer. The printed luminescent patterns exhibited multi-level and highly secured AC features. Unlike conventional luminescent AC technology that solely relies on luminescent molecules/nanoparticles, the new technique utilizes the following features to fight counterfeiting: (1) the combination of luminescent oxygen sensitive probes (OSP) and the oxygen permeable matrix (OPM), (2) the unique nonlinear oxygen-responsive behavior, (3) the local oxygen concentration, and (4) a luminescence lifetime reading device. Due to the non-linear behavior of luminescence oxygen sensor materials and large varieties of OSP and OPM, security information can be subtly hidden in the “ocean” of OSP-OPM combination. This combinatorial chemistry strategy makes it very difficult for counterfeiters to find the right composition even when the chemical composition of the luminescent molecules/nanoparticles was known. Information encrypted via this new methodology exhibits extremely high security, as counterfeiters need to identify all (not a part of them) the following security measures: (1) the right combination of OSP and OPM, (2) the right chemical stimulus (here is oxygen), (3) the proper oxygen concentration, and (4) the correct luminescence lifetime values.