Electrically conductive polymeric compositions, contacts, assemblies and methods
View Patent ↗Electrically conductive polymeric compositions adapted for use in forming electronic devices are disclosed. The compositions are thermally curable at temperatures less than about 250° C. Compositions are provided which may be solvent-free and so can be used in processing or manufacturing operations without solvent recovery concerns. The compositions utilize (i) fatty acid modified epoxy acrylate and/or methacrylate monomer(s) and/or oligomer(s), (ii) fatty acid modified polyester acrylate and/or methacrylate monomer(s) and/or oligomer(s), or combinations of (i) and (ii). Also described are electronic assemblies such as solar cells using the various compositions and related methods.
1. An electrically conductive, thermally curable composition comprising:
from about 70% to about 90% by weight of electrically conductive silver particles; and
from about 0.1% to about 30% by weight of a selection from the group consisting of (i) fatty acid modified epoxy acrylate and/or methacrylate monomer(s) or oligomer(s), (ii) fatty acid modified polyester acrylate and/or methacrylate monomer(s) or oligomer(s), and (iii) combinations of (i) and (ii);
wherein the composition is solvent-free and in the form of a paste that can be screen printed onto a substrate and thereafter cured at a temperature of less than 250° C. to form an electrically conductive contact, trace, circuit and/or other electrically conductive region.
2. The composition of claim 1 further comprising:
an effective amount of a reactive diluent.
3. The composition of claim 1 further comprising:
an effective amount of a free radical initiator.
4. The composition of claim 1 wherein the composition includes from about 0.1% to about 30% by weight of fatty acid modified epoxy acrylate and/or methacrylate monomer(s) or oligomer(s).
5. The composition of claim 1 wherein the composition includes from about 0.1% to about 30% by weight of fatty acid modified polyester acrylate and/or methacrylate monomer(s) or oligomer(s).
6. The composition of claim 1 wherein the composition includes from about 0.1% to about 30% by weight of a combination of (i) fatty acid modified epoxy acrylate and/or methacrylate monomer(s) or oligomer(s), and (ii) fatty acid modified polyester acrylate and/or methacrylate monomer(s) or oligomer(s).
7. The composition of claim 1 further comprising:
an epoxy triacrylate oligomer.
8. The composition of claim 7 wherein the epoxy triacrylate oligomer is aliphatic.
9. The composition of claim 7 wherein the epoxy triacrylate oligomer is used at a concentration of from about 0.1% to about 25%.
10. The composition of claim 2 wherein the reactive diluent is hexane diol diacrylate.
11. The composition of claim 10 wherein the hexane diol diacrylate is used at a concentration of from about 1% to about 10%.
12. The composition of claim 10 wherein the hexane diol diacrylate is used at a concentration of from about 4% to about 7%.
13. The composition of claim 3 wherein the free radical initiator is selected from the group consisting of (i) 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexyne, (ii) dicumyl peroxide, and combinations thereof.
14. The composition of claim 3 wherein the free radical initiator is at a concentration of from about 0.01% to about 2%.
15. The composition of claim 3 wherein the free radical initiator is at a concentration of about 0.3%.