Lanthanides doped NaLaMgWO phosphors for anti-counterfeit applications.

Luminescence of NaLaMgWO doped with lanthanide activators Tb, Eu and Er are reported. These activators exhibit characteristic emission spectra. Either the emission colour or the excitation spectrum distinguishes between these activators. This fact can be exploited for anti-counterfeit applications. Results demonstrating the applications are presented. The luminescent markers using Tb and Eu phosphors are seen as green and red under illumination by 275 nm and 315 nm light emitting diodes, respectively. Combination of Eu and Er can also be used. In this case the markers are seen as red and green under illumination by 315 nm and 375 nm light emitting diodes, respectively.