AIR STABLE COPPER NANOPARTICLE INK AND APPLICATIONS THEREFOR

• US 20090142481A1
• Filed: 11/30/2007
• Published: 06/04/2009
• Est. Priority Date: 11/30/2007
• Status: Active Grant

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: WORDEN, Matthew, KAZMAIER, Peter M., Chopra, Naveen
• Granted Patent: US 7,976,733 B2
• Time in Patent Office: Days
• US Class Current: 427/123
• CPC Class Codes: C09D 11/037 characterised by the pigment
• CPC Class Codes: C09D 11/38 characterised by non-macromolecular additives other than solvents, pigments or dyes
• CPC Class Codes: C09D 11/52 Electrically conductive inks
• CPC Class Codes: H05K 1/097 Inks comprising nanoparticles and specially adapted for being sintered at low temperature H05K1/095 takes precedence
• CPC Class Codes: H05K 2203/013 Inkjet printing, e.g. for printing insulating material or resist using ink-jet printing to form a conductive pattern H05K3/125
• CPC Class Codes: H05K 2203/122 Organic non-polymeric compounds, e.g. oil, wax, thiol using solvent H05K2203/0783
• CPC Class Codes: H05K 3/125 by ink-jet printing

Abstract

Low-cost copper nanoparticle inks that can be annealed onto paper substrate for RFID antenna applications, using substituted dithiocarbonates as stabilizers during copper nanoparticle ink production.

Claims

1. A copper nanoparticle ink composition, comprising:

copper nanoparticles;

a substituted dithiocarbonate stabilizer; and

a carrier solvent;

wherein the stabilizer stabilizes the copper nanoparticles.

2. The copper nanoparticle ink composition according to claim 1, wherein the substituted dithiocarbonate stabilizer is an alkyl xanthate compound having the formula:

R-o-C(═

S)S⁻

M⁺

wherein M is a counter cation; and

R is a substituted or unsubstituted organic group having from 1 to about 20carbons.

3. The copper nanoparticle ink composition according to claim 2, wherein R is selected from the group consisting of:

a substituted or unsubstituted straight or branched alkyl group;

a substituted or unsubstituted aryl group;

a substituted or unsubstituted straight or branched aralkyl or alkaryl group;

a substituted or unsubstituted straight or branched alkoxy group having 1 to about 5 oxygen atoms; and

a substituted or unsubstituted straight or branched aryloxy group having 1 to about 5 oxygen atoms.

4. The copper nanoparticle ink composition according to claim 2, wherein M is selected from the group consisting of H, Li, Na, K, Rb and Cs.

5. The copper nanoparticle ink composition according to claim 2, wherein the carrier solvent is dichloromethane.

6. The copper nanoparticle ink composition according to claim 1, wherein the substituted dithiocarbonate stabilizer is an ether alcohol based xanthate compound of formula:

R₁-X-R₂-C(═

S)S⁻

M⁺

wherein M is counter cation;

each of R₁ and R₂ is independently a substituted or unsubstituted organic group having from 1 to about 20 carbon atoms, optionally having one or more heteroatoms; and

X is a heteroatom.

7. The copper nanoparticle ink composition according to claim 6, wherein each of R₁ and R₂ independently is selected from a group consisting of;

a substituted or unsubstituted straight or branched alkyl groups;

a substituted or unsubstituted aryl group; and

a substituted or unsubstituted straight or branched aralkyl or alkaryl group.

8. The copper nanoparticle ink composition according to claim 6, wherein M is selected from the group consisting of H, Li, Na, K, Rb and Cs.

9. The copper nanoparticle ink composition according to claim 6, wherein the carrier solvent is selected from a group consisting of MEK, toluene, and dichloromethane, toluene, benzene, nitrobenzene, xylene, dichlorobenzene, mesitylene, hexane, and isopar.

10. The copper nanoparticle ink composition according to claim 1, wherein the ink is printed and annealed onto a substrate in an ambient environment.

11. The copper nanoparticle ink composition according to claim 1, wherein the copper nanoparticles have an average particle size from about 1 to about 500 nm.

12. The copper nanoparticle ink composition according to claim 1, wherein the ink is used to form conductive lines for RFID antenna applications.

13. A process for forming a copper nanoparticle ink composition, comprising:

providing a substituted dithiocarbonate stabilizer; and

stabilizing a copper nanoparticle dispersion with the substituted dithiocarbonate stabiizer in a solvent medium.

14. The process according to claim 13, wherein the substituted dithiocarbonate stabilizer is an alkyl xanthate compound having the formula:

R-O-C(═

S)S⁻

M⁺

wherein M is a counter cation; and

R is a substituted or unsubstituted organic group having from 1 to about 20carbons.

15. The process according to claim 14, wherein R is selected from the group consisting of:

a substituted or unsubstituted straight or branched alkyl group;

a substituted or unsubstituted aryl group;

a substituted or unsubstituted straight or branched aralkyl or alkaryl group;

a substituted or unsubstituted straight or branched alkoxy group having 1 to about 5 oxygen atoms; and

a substituted or unsubstituted straight or branched aryloxy group having 1 to about 5 oxygen atoms.

16. The process according to claim 14, wherein the carrier solvent is dichloromethane.

17. The process according to claim 13, wherein the substituted dithiocarbonate stabilizer is an ether alcohol based xanthate compound of formula:

R₁-X-R₂-C(═

S)S⁻

M⁺

wherein M is counter cation;

each of R₁ and R₂ is independently a substituted or unsubstituted organic group having from 1 to about 20 carbon atoms, optionally having one or more heteroatoms; and

X is a heteroatom.

18. The process according to claim 17, wherein each of R₁ and R₂independently is selected from the group consisting of:

a substituted or unsubstituted straight or branched alkyl group;

a substituted or unsubstituted aryl group; and

a substituted or unsubstituted straight or branched aralkyl or alkaryl group.

19. The process according to claim 17, wherein the carrier solvent is selected from a group consisting of MEK, toluene, dichloromethane, toluene, benzene, nitrobenzene, xylene, dichlorobenzene, mesitylene, hexane, and isopar,

20. A process for forming conductive lines on a substrate, comprising:

printing a copper nanoparticle ink composition onto a substrate in an ambient

environment; and

annealing the ink onto the substrate in an ambient environment.

21. The process according to claim 20, wherein the conductive lines are for RFID antenna applications,

22. The process according to claim 20, wherein the copper nanoparticles do not oxidize to non-conductive copper species prior to the annealing.