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 method for fabricating a voltage switchable dielectric material comprising:
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;
mixing the resin until the first, second, and third semiconductive materials are uniformly dispersed in the resin; and
curing the resin, wherein curing includes exposing the resin to a plurality of curing periods, wherein at least one of the curing periods is at a higher temperature than the immediately preceding curing period.
2. The method of claim 1 wherein mixing includes sonication.
3. The method of claim 1 wherein mixing is performed with a rotor-stator mixer.
4. The method of claim 1 further comprising adding a solvent to the resin during mixing.
5. The method of claim 1 wherein the solvent comprises N-methyl-2 pyrrolidone.
6. The method of claim 1 further comprising adding a conductive material to the resin before mixing the resin.
7. The method of claim 1 wherein at least one of the first, second, or third semiconductive materials comprises a solvent soluble organic material.
8. A method for fabricating a voltage switchable dielectric material comprising:
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;
mixing the resin until the first, second, and third semiconductive materials are uniformly dispersed in the resin, and adding a solvent to the resin during mixing; and
curing the resin.
9. The method of claim 8 wherein mixing includes sonication.
10. The method of claim 8 wherein mixing is performed with a rotor-stator mixer.
11. The method of claim 8 wherein curing the resin includes exposing the resin to a plurality of curing periods, wherein at least one of the curing periods is at a higher temperature than the immediately preceding curing period.
12. The method of claim 8 wherein the solvent comprises N-methyl-2 pyrrolidone.
13. The method of claim 8 further comprising adding a conductive material to the resin before mixing the resin.
14. The method of claim 8 wherein at least one of the first, second, or third semiconductive materials comprises a solvent soluble organic material.
15. A method for fabricating a voltage switchable dielectric material comprising:
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, wherein at least one of the first, second, or third semiconductive materials comprises a solvent soluble organic material;
mixing the resin until the first, second, and third semiconductive materials are uniformly dispersed in the resin; and
curing the resin.
16. The method of claim 15 , wherein the soluble organic semiconductor material is at least one of carbon, carbon nanotubes, and carbon fullerenes.
17. The method of claim 15 , wherein the soluble organic semiconductor material is a covalently bonded chemical group or moiety of a nanotube.
18. The method of claim 15 , 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).
19. The method of claim 15 , 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.
20. The method of claim 15 , wherein the soluble organic semiconductor material is a photo-active organic material.
21. The method of claim 15 , wherein the soluble organic semiconductor material is polythiophene.
22. The method of claim 15 wherein mixing includes sonication.
23. The method of claim 15 wherein mixing is performed with a rotor-stator mixer.
24. The method of claim 15 wherein curing includes exposing the resin to a plurality of curing periods, wherein at least one of the curing periods is at a higher temperature than the immediately preceding curing period.
25. The method of claim 15 further comprising adding a solvent to the resin during the mixing process.
26. The method of claim 15 wherein the solvent comprises N-methyl-2 pyrrolidone.
27. The method of claim 15 further comprising adding a conductive material to the resin before mixing the resin.
28. An electronic device comprising a voltage switchable dielectric (VSD) material, the VSD material comprising:
a resin;
a first, a second, and a third semiconductive material, each of the first, second, and third semiconductive materials being characterized by a different bandgap energy; wherein
at least one of the first, second, or third semiconductive materials comprises a solvent soluble organic material;
the first, second, and third semiconductive materials are dispersed in the resin; and
the VSD material is cured.
29. The electronic device of claim 28 , wherein the electronic device is at least one of a printed circuit board, a semiconductor package, a radio frequency identification (RFID) tag, a light emitting diode (LED), a display backplane, or a discrete surge suppressing device.
30. The electronic device of claim 28 , wherein the soluble organic semiconductor material is at least one of carbon, carbon nanotubes, and carbon fullerenes.
31. The electronic device of claim 28 , wherein the soluble organic semiconductor material is a covalently bonded chemical group or moiety of a nanotube.
32. The electronic device of claim 28 , 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).
33. The electronic device of claim 28 , 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.
34. The electronic device of claim 28 , wherein the soluble organic semiconductor material is a photo-active organic material.
35. The electronic device of claim 28 , wherein the soluble organic semiconductor material is polythiophene.