PLASMONIC ENHANCEMENT OF MATERIAL PROPERTIES

• US 20130201544A1
• Filed: 02/01/2013
• Published: 08/08/2013
• Est. Priority Date: 02/03/2012
• Status: Active Grant

• Current Assignee: National Institute of Standards and Technology (Government of the United States of America), University of Maryland, College Park
• Original Assignee: National Institute of Standards and Technology (Government of the United States of America)
• Inventors: Lezec, Henri J., Walter, Erich C., Agrawal, Amit, Talin, Albert Alec, Xu, Ting
• Granted Patent: US 9,046,731 B2
• Time in Patent Office: Days
• US Class Current: 359/265
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G02F 1/15165 Polymers
• CPC Class Codes: G02F 1/1533 structural features not otherwise provided for
• CPC Class Codes: G02F 2203/10 plasmon
• CPC Class Codes: G09G 3/38 using electrochromic devices

Abstract

Various plasmonic structures in the form of electrochromic optical switches are described which exhibit relatively high optical switching contrast. The switches generally include a collection of nanoslits formed in a thin electrically conductive film. An electrochromic material is disposed on the conductive film and along the sidewalls of the nanoslit(s).

Claims

1. A plasmonic structure comprising:

a substrate;

an electrically conductive film disposed on the substrate, the film defining an outer face, the film also defining at least one nanoslit extending through at least a portion of the thickness of the film, the nanonslit defining opposing sidewalls; and

an effective amount of an electrochromic material disposed on the sidewalls of the nanoslit.

2. The plasmonic structure of claim 1 wherein the at least one nanoslit extends though the entirety of the thickness of the film.

3. The plasmonic structure of claim 1 wherein the substrate is selected from the group consisting of fused silica, fused quartz, and glass.

4. The plasmonic structure of claim 1 wherein the electrically conductive film is selected from the group consisting of gold, silver, aluminum, indium tin oxide, and combinations thereof.

5. The plasmonic structure of claim 1 wherein the electrically conductive film is from about 50 nm to about 500 nm in thickness.

6. The plasmonic structure of claim 1 wherein the nanoslit has a width of from about 10 nm to about 100 nm.

7. The plasmonic structure of claim 6 wherein the nanoslit has a width of about 50 nm.

8. The plasmonic structure of claim 1 wherein the electrochromic material is in the form of a layer of nanoparticles having a thickness of from about 1 nm to about 100 nm.

9. The plasmonic structure of claim 1 wherein the layer of nanoparticles of electrochromic material is an electrochromic polymer.

10. The plasmonic structure of claim 1 wherein the effective amount of the electrochromic material is such that the fill fraction of the electrochromic material in the nanoslit is from about 10% to about 30%.

11. The plasmonic structure of claim 10 wherein the fill fraction is about 25%.

12. The plasmonic structure of claim 1 wherein the plasmonic structure is in the form of an optical switch and exhibits an optical switching contrast of at least 70%.

13. The plasmonic structure of claim 12 wherein the switch exhibits an optical switching contrast of at least 80%.

14. The plasmonic structure of claim 13 wherein the switch exhibits an optical switching contrast of at least 90%.

15. An electrochromic device comprising:

a fluid medium in the form of an electrolyte;

a plurality of plasmonic structures, each plasmonic structure including (i) a substrate, (ii) an electrically conductive film disposed on the substrate, the film defining an outer face and at least one nanoslit extending through at least a portion of the thickness of the film, the nanoslit defining opposing sidewalls, and (iii) an effective amount of an electrochromic material disposed on the sidewalls of the nanoslit;

wherein each of the plurality of plasmonic structures are exposed to, and in contact with, the fluid medium along the outer face and within the nanoslit of the plasmonic structure.

16. The electrochromic device of claim 15 wherein the at least one nanoslit extends through the entirety of the thickness of the film.

17. The electrochromic device of claim 15 wherein the nanoslit has a width of from about 10 nm to about 100 nm.

18. The electrochromic device of claim 15 wherein the electrochromic material is in the form of a layer of nanocrystals disposed on the sidewalls of the nanoslit and having a thickness of from about 1 nm to about 100 nm.

19. The electrochromic device of claim 15 wherein the effective amount of the electrochromic material is such that the fill fraction of the electrochromic material in the nanoslit is from about 10% to about 30%

20. A plasmonic electrochromic optical switch comprising:

a substrate;

a layer of an electrically conductive material disposed on the substrate, the layer of electrically conductive material defining a top face, the layer of electrically conductive material selected from the group consisting of gold, silver, aluminum, indium tin oxide, and combinations thereof;

at least one nanoslit defined in the layer of electrically conductive material, the nanoslit extending through at least a portion of the thickness of the electrically conductive material, the nanoslit defining opposing sidewalls;

a layer of an electrochromic polymer disposed on the top face of the electrically conductive material and on the nanoslit sidewalls;

an electrolyte in contact with the layer of the electrochromic polymer and disposed between the opposing sidewalls of the nanoslit.

21. The plasmonic electrochromic optical switch of claim 20 wherein the nanoslit has a width of from about 10 nm to about 100 nm and the thickness of the layer of the electrochromic polymer is from about 1 nm to about 100 nm.

22. The plasmonic electrochromic optical switch of claim 20 wherein the nanoslit extends through the entirety of the thickness of the electrically conductive material.

23. A method of improving performance of a plasmonic device utilizing an electrically conductive film disposed on a substrate, the method comprising:

incorporating an effective amount of an electrochromic material in the plasmonic device.

24. The method of claim 23 wherein the plasmonic device includes at least one nanoslit defining opposing sidewalls, whereby incorporating the electrochromic material is performed by depositing an effective amount of the electrochromic material on the sidewalls of the nanoslit.