Invisible-fluorescent identification tags for materials

1. A taggant composition, comprising:

a first and a second taggant material that are each invisible in light of the visible spectrum and fluoresce under a non-visible excitation energy;

as binder; and

a solvent, wherein the first and second taggant materials and the binder are dissolved in the solvent.

2. The taggant composition of claim 1 wherein the first and second taggant materials each comprise at least one of a dye, nanoparticle, or phosphor.

3. The taggant composition of claim 1 wherein at least one of the first and second taggant materials comprises a cyanine compound.

4. The taggant composition of claim 1 wherein at least one of the first and second taggant materials fluoresces in infrared or near-infrared light.

5. The taggant composition of claim 1 wherein the binder comprises a polymer selected from the group consisting of polystyrene, poly(styrene-co-allyl alcohol), poly(vinyl butyral), poly(ethyleneimine), poly(hydroxyethyl methacrylate), poly(vinylpyrrolidone), and combinations thereof.

6. The taggant composition of claim 1 wherein the solvent comprises methyl ethyl ketone, methyl isobutyl ketone, chloroform, dimethyl sulfoxide, acetone, methanol, ethanol, ethyl acetate, or combinations thereof.

7. A method of tagging a material using the taggant composition of claim 1 , the method comprising applying the taggant composition to a material to be tagged to form an indicium.

8. The method of claim 7 further comprising applying the taggant composition via at least one of an ink-jet printer or a stamp pad.

9. A taggant article comprising a material substrate including the taggant composition of claim 1 to form a taggant on the material substrate.

10. The tagged article of claim 9 wherein the taggant provides an indicium comprising at least one of:

a detectable presence of at least one wavelength of fluoresced non-visible light;

a quantifiable concentration of at least one specific wavelength of fluoresced non-visible light; or

a readable pattern on the material substrate.

11. The tagged article of claim 9 wherein the taggant provides an indicium comprising a readable pattern comprising a barcode.

12. The tagged article of claim 9 wherein the taggant provides an indicium comprising a readable pattern comprising an array pattern.

13. The tagged article of claim 9 wherein the taggant composition comprises a least three different taggant materials that in combination provide an indicium comprising a characteristic fluorescence wavelength spectrum.

14. An apparatus for reading the tagged article of claim 9 the apparatus comprising:

an emitter capable of emitting the excitation energy to induce the taggant material to fluoresce; and

a detector in combination with the emitter, wherein the detector detects the fluorescing taggant material.

15. The apparatus of claim 14 wherein the detector comprises a pattern recognition module and a display module in combination with a user interface.

16. The apparatus of claim 14 wherein the detector comprises a spectrometer.

17. A method of tagging a material, the method comprising:

applying first and second taggant compositions to a material to be tagged to form an indicium, said first and second taggant compositions each comprising:

taggant material that is invisible in light of the visible spectrum and fluoresces under a non-visible excitation energy;

a binder; and

solvent, wherein the taggant material and the binder are dissolved in the solvent.

18. A taggant composition, comprising:

a taggant material that is invisible in light of the visible spectrum and fluoresces under a non-visible excitation energy, the taggant material comprising a cyanine compound;

a binder; and

a solvent, wherein the taggant material and the binder are dissolved in the solvent.