Lithographically defined microporous carbon structures
View Patent ↗A lithographic method is used to fabricate porous carbon structures that can provide electrochemical electrodes having high surface area with uniform and controllable dimensions, providing enormous flexibility to tailor the electrodes toward specific applications. Metal nanoparticles deposited on the surface of the porous carbon electrodes exhibit ultra small dimensions with uniform size distribution. The resulting electrodes are rugged, electrically conductive and show excellent electrochemical behavior.
1. A method for fabricating a lithographically defined microporous carbon structure, comprising:
depositing a carbon-containing photoresist onto a substrate,
lithographically defining a three-dimensional microporous structure in the deposited photoresist,
developing the lithographically defined photoresist, and
pyrolyzing the developed photoresist to provide a three-dimensional microporous carbon structure.
2. The method of claim 1 , further comprising depositing metal nanoparticles onto the three-dimensional microporous carbon structure.
3. The method of claim 2 , wherein the metal nanoparticles comprise gold nanoparticles.
4. The method of claim 2 , further comprising depositing a catalytic metal onto the metal nanoparticles.
5. The method of claim 4 , wherein the catalytic metal comprises palladium or platinum.
6. The method of claim 2 , wherein the depositing metal nanoparticles comprises electrodepositing metal nanoparticles.
7. The method of claim 1 , further comprising depositing a conducting polymer onto the three-dimensional microporous carbon structure.
8. The method of claim 7 , wherein the conducting polymer comprises poly(pyrrole) or poly(bithiophene).
9. The method of claim 1 , wherein the lithographically defining step comprises defining the three-dimensional microporous structure using interferometric lithography.
10. The method of claim 9 , wherein the interferometric lithography comprises two-step interference.
11. The method of claim 1 , wherein the substrate comprises silicon, fused silica, or aluminum oxide.
12. The method of claim 1 , further comprising depositing a bottom anti-reflection coating on the substrate before depositing the carbon-containing photoresist.
13. The method of claim 1 , wherein the carbon-containing photoresist comprises a negative resist.
14. The method of claim 1 , wherein the carbon-containing photoresist comprises a positive resist.
15. The method of claim 1 , wherein the carbon-containing photoresist comprises a photodefinable polymer.
16. The method of claim 15 , wherein the photodefinable polymer comprises an epoxy.
17. The method of claim 15 , wherein the photodefinable polymer comprises a phenolic resin or a novolac resin.
18. The method of claim 1 , wherein the pyrolyzing step comprises heating the developed photoresist to a temperature greater than 900° C.
19. The method of claim 1 , wherein the pore size of the three-dimensional microporous carbon structure is less than 1 micron.
20. The method of claim 1 , wherein the pore size of the three-dimensional microporous carbon structure is less than 0.1 microns.