Formulations for voltage switchable dielectric materials having a stepped voltage response and methods for making the same
Formulations for voltage switchable dielectric materials include two or more different types of semiconductive materials uniformly dispersed within a dielectric matrix material. The semiconductive materials are selected to have different bandgap energies in order to provide the voltage switchable dielectric material with a stepped voltage response. The semiconductive materials may comprise inorganic particles, organic particles, or an organic material that is soluble in, or miscible with, the dielectric matrix material. Formulations optionally can also include electrically conductive materials. At least one of the conductive or semiconductive materials in a formulation can comprise particles characterized by an aspect ratio of at least 3 or greater.
1. A voltage switchable dielectric material made by the process of:
adding first, second, and third semiconductive materials to a resin, each of the first, second, and third semiconductive materials being characterized by a different bandgap energy;
adding a solvent comprising N-methyl-2 pyrrolidone;
mixing the resin until the first, second, and third semiconductive materials are uniformly dispersed in the resin; and
curing the resin.
2. The voltage switchable dielectric material of claim 1 wherein mixing includes sonication.
3. The voltage switchable dielectric material of claim 1 wherein mixing is performed with a rotor-stator mixer.
4. The voltage switchable dielectric material of claim 1 wherein curing the resin includes exposing the resin to a plurality of curing periods, wherein each successive curing period is at a higher temperature than the previous curing period.
5. The voltage switchable dielectric material of claim 1 further comprising adding a conductive material to the resin before mixing the resin.
6. The voltage switchable dielectric material of claim 1 wherein at least one of the first, second, or third semiconductive materials comprises a solvent soluble organic semiconductor material.
7. The voltage switchable dielectric material of claim 6 , wherein the soluble organic semiconductor material is at least one of carbon, carbon nanotubes, and carbon fullerenes.
8. The voltage switchable dielectric material method of claim 6 , wherein the soluble organic semiconductor material is a covalently bonded chemical group or moiety of a nanotube.
9. The voltage switchable dielectric material of claim 6 , wherein the soluble organic semiconductor material is at least one of poly-3-hexylthiophene, polythiophene, polyacteylene, poly (3,4-ethylenedioxythiophene), poly(styrenesulfonate), pentacene, (8-hydroxyquinolinolato) aluminum (III), or N,N′-di-[(naphthalenyl)-N,N′diphenyl]-1, 1′-biphenyl-4,4′-diamine (NPD).
10. The voltage switchable dielectric material of claim 6 , wherein the soluble organic semiconductor material is derived from at least one of a monomer, oligomer, or polymer of thiophene, analine, phenylene, vinylene, fluorene, naphthalene, pyrrole, acetylene, carbazole, pyrrolidone, cyano materials, anthracene, pentacene, rubrene, perylene, or oxadizole.
11. The voltage switchable dielectric material of claim 6 , wherein the soluble organic semiconductor material is a photo-active organic material.
12. The voltage switchable dielectric material of claim 6 , wherein the soluble organic semiconductor material is polythiophene.
13. The voltage switchable dielectric material of claim 6 further comprising adding a solvent, the solvent comprising N-methyl-2 pyrrolidone.
14. A voltage switchable dielectric material made by the process of:
adding first, second, and third semiconductive materials to a resin, each of the first, second, and third semiconductive materials being characterized by a different bandgap energy, at least one of the first, second, or third semiconductive materials comprising a solvent soluble photo-active organic semiconductor material;
mixing the resin until the first, second, and third semiconductive materials are uniformly dispersed in the resin; and
curing the resin.
15. The voltage switchable dielectric material of claim 14 wherein mixing includes sonication.
16. The voltage switchable dielectric material of claim 14 wherein mixing is performed with a rotor-stator mixer.
17. The voltage switchable dielectric material of claim 14 wherein curing the resin includes exposing the resin to a plurality of curing periods, wherein each successive curing period is at a higher temperature than the previous curing period.
18. The voltage switchable dielectric material of claim 14 further comprising adding a solvent to the resin during mixing.
19. The voltage switchable dielectric material of claim 18 wherein the solvent comprises N-methyl-2 pyrrolidone.
20. The voltage switchable dielectric material of claim 14 further comprising adding a conductive material to the resin before mixing the resin.
21. The voltage switchable dielectric material of claim 14 , wherein the soluble organic semiconductor material is at least one of carbon, carbon nanotubes, and carbon fullerenes.
22. The voltage switchable dielectric material method of claim 14 , wherein the soluble organic semiconductor material is a covalently bonded chemical group or moiety of a nanotube.
23. The voltage switchable dielectric material of claim 14 , wherein the soluble organic semiconductor material is at least one of poly-3-hexylthiophene, polythiophene, polyacteylene, poly (3,4-ethylenedioxythiophene), poly(styrenesulfonate), pentacene, (8-hydroxyquinolinolato) aluminum (III), or N,N′-di-[(naphthalenyl)-N,N′diphenyl]-1, 1′-biphenyl-4,4′-diamine (NPD).
24. The voltage switchable dielectric material of claim 14 , wherein the soluble organic semiconductor material is derived from at least one of a monomer, oligomer, or polymer of thiophene, analine, phenylene, vinylene, fluorene, naphthalene, pyrrole, acetylene, carbazole, pyrrolidone, cyano materials, anthracene, pentacene, rubrene, perylene, or oxadizole.
25. The voltage switchable dielectric material of claim 14 , wherein the soluble organic semiconductor material is polythiophene.
26. The voltage switchable dielectric material of claim 14 further comprising adding a solvent, the solvent comprising N-methyl-2 pyrrolidone.
27. A voltage switchable dielectric material made by the process of:
adding first, second, and third semiconductive materials to a resin, each of the first, second, and third semiconductive materials being characterized by a different bandgap energy, at least one of the first, second, or third semiconductive materials comprising N-methyl-2 pyrrolidone;
mixing the resin until the first, second, and third semiconductive materials are uniformly dispersed in the resin; and
curing the resin.
28. The voltage switchable dielectric material of claim 27 wherein mixing includes sonication.
29. The voltage switchable dielectric material of claim 27 wherein mixing is performed with a rotor-stator mixer.
30. The voltage switchable dielectric material of claim 27 wherein curing the resin includes exposing the resin to a plurality of curing periods, wherein each successive curing period is at a higher temperature than the previous curing period.
31. The voltage switchable dielectric material of claim 27 further comprising adding a solvent to the resin during mixing.
32. The voltage switchable dielectric material of claim 31 wherein the solvent comprises N-methyl-2 pyrrolidone.
33. The voltage switchable dielectric material of claim 27 further comprising adding a conductive material to the resin before mixing the resin.
34. The voltage switchable dielectric material of claim 27 , wherein the soluble organic semiconductor material is at least one of carbon, carbon nanotubes, and carbon fullerenes.
35. The voltage switchable dielectric material of claim 27 , wherein the soluble organic semiconductor material is a covalently bonded chemical group or moiety of a nanotube.
36. The voltage switchable dielectric material of claim 27 , wherein the soluble organic semiconductor material is at least one of poly-3-hexylthiophene, polythiophene, polyacteylene, poly (3,4-ethylenedioxythiophene), poly(styrenesulfonate), pentacene, (8-hydroxyquinolinolato) aluminum (III), or N,N′ -di- [(naphthalenyl)-N,N′diphenyl]-1, 1′-biphenyl-4,4′-diamine (NPD).
37. The voltage switchable dielectric material of claim 27 , wherein the soluble organic semiconductor material is derived from at least one of a monomer, oligomer, or polymer of thiophene, analine, phenylene, vinylene, fluorene, naphthalene, pyrrole, acetylene, carbazole, pyrrolidone, cyano materials, anthracene, pentacene, rubrene, perylene, or oxadizole.
38. The voltage switchable dielectric material of claim 27 , wherein the soluble organic semiconductor material is a photo-active organic material.
39. The voltage switchable dielectric material of claim 27 , wherein the soluble organic semiconductor material is polythiophene.