Abstract: Luminescent phosphor systems, methods of preparing luminescent phosphor systems, and articles that include the luminescent phosphor systems are provided herein. In an embodiment, a luminescent phosphor system includes a plurality of separate luminescent phosphor lots. The plurality of luminescent phosphor lots includes a first lot of a first luminescent phosphor compound and a second lot of a second luminescent phosphor compound. The first luminescent phosphor compound of the first lot includes zinc sulfide, copper ions, halogen ions and, optionally, at least one additional metal ion chosen from aluminum, manganese, and/or iron. The second luminescent phosphor compound of the second lot includes zinc sulfide, copper ions, halogen ions, and at least one additional metal ion chosen from aluminum and/or manganese. The first luminescent phosphor compound and the second luminescent phosphor compound have different decay time constants that are distinguishable by an authentication device.

Abstract: The invention relates to anti-Stokes fluorescent material compositions which, upon excitation by IR radiation, emits IR radiation without significant quantities of visible blue light being emitted at the same time, and which are therefore suitable as invisible security marks.

Abstract: The invention relates to anti-Stokes fluorescent material compositions which, upon excitation by IR radiation, emits IR radiation without significant quantities of visible blue light being emitted at the same time, and which are therefore suitable as invisible security marks.

Abstract: Non-green anti-Stokes luminescent material, comprising the elements Ln, erbium (Er) and ytterbium (Yb), Ln representing at least one element which is selected from the group consisting of yttrium (Y), gadolinium (Gd), scandium (Sc) and lanthanum (La), a process for its production and its use.