Method of minimizing absorption of visible light in infrared dyes
The present invention provides a method of minimizing absorption of visible light in an IR-absorbing dye comprising reducing intermolecular interactions between adjacent dye molecules. The method is particularly suitable for use in connection with netpage and Hyperlabel systems.
1. A method of minimizing absorption of visible light in an IR-absorbing dye comprising reducing intermolecular interactions between adjacent dye molecules, wherein said dye comprises a substantially planar π-system and the intermolecular interactions are π-π interactions.
2. The method of claim 1 , wherein the intermolecular interactions are reduced by steric repulsion.
3. The method of claim 1 , wherein the dye molecule comprises at least one moiety, which extends out of the plane of the substantially planar π-system.
4. The method of claim 1 , wherein the intermolecular interactions are reduced using a bridged cyclic group.
5. The method of claim 1 , wherein the intermolecular interactions are reduced using a polymeric group.
6. The method of claim 5 , wherein the polymeric group is a dendrimer.
7. The method of claim 5 , wherein the polymeric group includes a PEG chain.
8. The method of claim 1 , wherein the IR-absorbing dye is a metal-ligand dye.
9. The method of claim 8 , wherein the IR-absorbing dye is a metal-cyanine dye.
10. The method of claim 8 , wherein the IR-absorbing dye is a metal-dithiolene dye.
11. The method of claim 8 comprising preselecting a metal-ligand dye, wherein at least one ligand includes a bridged cyclic group.
12. The method of claim 8 comprising preselecting a metal-ligand dye, wherein at least one ligand includes a polymeric group.
13. The method of claim 8 comprising preselecting a metal-ligand dye, wherein at least one ligand includes a dendrimer.
14. The method of claim 8 comprising preselecting a metal-ligand dye, wherein at least one ligand includes a PEG chain.
15. A method of minimizing visible coloration of a substrate having an IR-absorbing dye disposed thereon, said method comprising reducing intermolecular interactions between adjacent dye molecules, wherein said dye comprises a substantially planar π-system and the intermolecular interactions are π-π interactions.
16. The method of claim 15 , wherein said dye is disposed in the form of coded data.
17. The method of claim 16 , wherein said substrate comprises an interface surface and wherein the coded data is disposed over a substantial portion of said interface surface.
18. The method claim 15 , wherein said substrate is a paper sheet, a label, a tag, a packaging material or a product item.