Metallic ink
A metallic ink including a vehicle, a multiplicity of copper nanoparticles, and an alcohol. The conductive metallic ink may be deposited on a substrate by methods including inkjet printing and draw-down printing. The ink may be pre-cured and cured to form a conductor on the substrate.
1. A conductive metal ink comprising:
a vehicle comprising two or more oxygenated organic compounds;
copper nanoparticles; and
a medium length chain aliphatic alcohol, wherein the ink does not comprise a binder.
2. The ink of claim 1 , wherein the medium length chain aliphatic alcohol has four to twelve carbon atoms, inclusive.
3. The ink of claim 2 , wherein the alcohol is isobutanol, 2-octanol, or a combination thereof.
4. The ink of claim 1 , wherein the viscosity of the alcohol exceeds the viscosity of the vehicle.
5. The ink of claim 1 , wherein the dielectric constant of the alcohol exceeds the dielectric constant of the vehicle.
6. The ink of claim 1 , wherein the alcohol is a non-polymeric alcohol.
7. The ink of claim 1 , wherein the alcohol comprises between about 30 wt % and about 96 wt % of organic liquids in the ink.
8. The ink of claim 1 , further comprising an ionic dispersant.
9. The ink of claim 8 , wherein the ionic dispersant comprises between about 0.5 wt % and 20 wt % of the ink.
10. The ink of claim 1 , wherein the copper nanoparticles comprise copper oxide.
11. The ink of claim 1 , wherein the copper nanoparticles comprise between about 40 wt % and about 60 wt % of the ink.
12. The ink of claim 1 , wherein the boiling point of the vehicle is less than 150° C.
13. The ink of claim 1 , wherein the vehicle is hydrophilic.
14. The ink of claim 1 , wherein the ink is substantially free of nanoparticle agglomerates larger than about 10 μm in diameter.
15. The ink of claim 1 , wherein the ink is curable to form a smooth, homogeneous conductor.
16. The ink of claim 1 , wherein the medium length chain aliphatic alcohol is not a polyol.
17. The ink of claim 1 , wherein the two or more oxygenated organic compounds each comprise a carbonyl group.
18. The ink of claim 1 , wherein the two or more oxygenated organic compounds each comprise an ether acetate.
19. The ink of claim 1 , wherein a concentration of the medium length chain aliphatic alcohol within the conductive metal ink is configured to achieve a monolayer coverage of the copper nanoparticles by head groups of the medium length chain aliphatic alcohol.
20. The ink of claim 1 , wherein the medium length chain aliphatic alcohol has a head group that is chemically compatible with the copper nanoparticles and a tail group that is chemically compatible with the vehicle.
21. The ink of claim 1 , wherein at least some plurality of the copper nanoparticles have a copper oxide layer that is hydrogen bonded to the medium length chain aliphatic alcohol.
22. The ink of claim 1 , wherein the alcohol is 2-octanol.
23. The ink of claim 1 , wherein the vehicle has a composition that is configured to interact with the copper nanoparticles and the alcohol so that it evaporates from the conductive metal ink when cured.
24. The ink of claim 23 , wherein a boiling point of the vehicle is less than 150° C.