AUTHENTICATING AND IDENTIFYING OBJECTS BY DETECTING MARKINGS THROUGH TURBID ...

1. A container for an object, comprising:

a substrate having an outer surface and an inner surface and including a turbid material; and

a marking adjacent to the inner surface and including a luminescent material that exhibits photoluminescence in response to incident light directed on the outer surface, the photoluminescence having a quantum efficiency of at least 20 percent and a peak emission wavelength in the near infrared range.

2. The container of claim 1, wherein the substrate defines an internal compartment, and the inner surface faces the internal compartment.

3. The container of claim 2, wherein the internal compartment is sized to accommodate the object, and the marking is a security marking to authenticate the object.

4. The container of claim 1, wherein the marking includes a binder and a plurality of particles dispersed in the binder, the plurality of particles including the luminescent material.

5. The container of claim 4, wherein the plurality of particles have sizes in the nanometer range.

6. The container of claim 5, wherein the plurality of particles are monodisperse with respect to the sizes of the plurality of nanoparticles.

7. The container of claim 1, wherein the luminescent material has the formula:

description="In-line Formulae" end="lead"[AaBbXx], description="In-line Formulae" end="tail"

wherein

A is selected from elements of Group IA;

B is selected from elements of Group VA, elements of Group IB, elements of Group IIB, elements of Group IIIB, elements of Group IVB, and elements of Group VB;

X is selected from elements of Group VIIB;

a is in the range of 1 to 5;

b is in the range of 1 to 3; and

x is in the range of 1 to 5.

8. The container of claim 7, wherein A is cesium, B is tin, and X is one of chlorine, bromine, and iodine.

9. The container of claim 7, wherein a is 1, b is 1, and x is 3.

10. The container of claim 7, wherein the luminescent material includes dopants.

11. The container of claim 10, wherein the dopants include electron acceptors and electron donors.

12. The container of claim 1, wherein the quantum efficiency is at least 30 percent.

13. The container of claim 1, wherein the photoluminescence has a spectral width that is no greater than 100 nm at Full Width at Half Maximum.

14. The container of claim 1, wherein the peak emission wavelength is in the range of 700 nm to 800 nm.

15. The container of claim 1, wherein the peak emission wavelength is in the range of 900 nm to 1 μm.

16. The container of claim 1, wherein the luminescent material produces emitted light in response to the incident light, and the container further comprises a reflective element adjacent to the marking to reflect at least a portion of the emitted light towards the outer surface.

17. A label for an object, comprising:

a substrate; and

a coating adjacent to the substrate and including a set of luminescent materials to provide an optical signature, at least one of the set of luminescent materials having the formula:

description="In-line Formulae" end="lead"[AaBbXx], description="In-line Formulae" end="tail"

wherein

A is selected from elements of Group IA;

B is selected from elements of Group VA, elements of Group IB, elements of Group IIB, elements of Group IIIB, elements of Group IVB, and elements of Group VB;

X is selected from elements of Group VIIB;

a is in the range of 1 to 9;

b is in the range of 1 to 5; and

x is in the range of 1 to 9.

18. The label of claim 17, wherein the coating is adjacent to the object when the label is coupled to the object.

19. The label of claim 17, wherein the substrate includes a turbid material, and at least one of the set of luminescent materials exhibits photoluminescence in response to incident light directed through the turbid material.

20. The label of claim 19, wherein the photoluminescence has: (a) a quantum efficiency of at least 20 percent; (b) a spectral width no greater than 100 nm at Full Width at Half Maximum; and (c) a peak emission wavelength in the near infrared range.

21. The label of claim 19, wherein the set of luminescent materials includes: (a) a first luminescent material having a first peak emission wavelength; and (b) a second luminescent material having a second peak emission wavelength that is different from the first peak emission wavelength.

22. The label of claim 17, wherein the coating includes a plurality of nanoparticles including the set of luminescent materials.

23. The label of claim 17, wherein B is selected from elements of Group IVB.

24. The label of claim 17, wherein A is cesium, B is tin, and X is one of chlorine, bromine, and iodine.

25. The container of claim 17, wherein a is in the range of 1 to 5, b is in the range of 1 to 3, and x is in the range of 1 to 5.

26. The container of claim 25, wherein a is 1, b is 1, and x is 3.