Solar thermoplasmonic nanofurnaces and method for making and using same

Patent metadata

Field	Value
Publication number	US-11319640-B2
Application number	US-202016865365-A
Country	US
Kind code	B2
Filing date	May 3, 2020
Priority date	May 3, 2019
Publication date	May 3, 2022
Grant date	May 3, 2022

Abstract

Titanium nitride (TiN) nanofurnaces are fabricated in a method that involves anodization of a titanium (Ti) foil to form TiO2 nanocavities. After anodization, the TiO2 nanocavities are converted to TiN at 600° C. under ammonia flow. The resulting structure is an array of refractory (high-temperature stable) subwavelength TiN cylindrical cavities that operate as plasmonic nanofurnaces capable of reaching temperatures above 600° C. under moderate concentrated solar irradiation. The nanofurnaces show near-unity solar absorption in the visible and near infrared spectral ranges and a maximum thermoplasmonic solar-to-heat conversion efficiency of 68 percent.

First claim

The invention claimed is:

1. A method of fabricating a device, comprising:
(a) anodizing titanium (Ti) foil to form titanium dioxide (TiO 2 ) nanocavities; and
(b) perform nitridization of the titanium dioxide nanocavities in ammonia atmosphere to form a plurality of titanium nitride (TiN) nanocavities.

2. The method of claim 1 , wherein the titanium foil has a thickness in the range of 0.1 mm to 1 mm.

3. The method of claim 1 , further comprising, before the anodization step (a), cleaning the titanium foil in acetone, ethanol and deionized water solutions under sonication.

4. The method of claim 1 wherein the anodization step (a) comprises:
(a1) employing the titanium foil as the working electrode;
(a2) employing a platinum foil as a counter electrode;
(a3) applying a voltage across the working electrode and the counter electrode.

5. The method of claim 4 , further comprising disposing the working electrode and counter electrode in an electrolyte composed of a mixture of hydrofluoric acid (HF) and phosphoric acid (H 3 PO 4 ) during the anodization step (a).

6. The method of claim 5 , wherein the hydrofluoric acid is provided in a predetermined concentration in the phosphoric acid to produce a predetermined diameter of the TiO 2 nanocavities.

7. The method of claim 6 , wherein the hydrofluoric acid is provided in a concentration of 3 molarity (3M).

8. The method of claim 7 , wherein the TiN nanocavities have a diameter of about 80 nm.

9. The method of claim 6 , wherein the hydrofluoric acid is provided in a concentration of 1-2M.

10. The method of claim 9 , wherein the TiN nanocavities have a diameter greater than 80 nm.

11. The method of claim 6 , wherein the hydrofluoric acid is provided in a concentration of 4-5M.

12. The method of claim 9 , wherein the TiN nanocavities have a diameter less than 80 nm.

13. The method of claim 4 , wherein step (a3) further comprises applying a DC voltage of between 10 volts and 30 volts to produce a predetermined diameter of the TiO 2 nanocavities.

14. The method of claim 13 , wherein step (a3) further comprises applying the DC voltage for a time period of one hour to three hours.

15. The method of claim 14 , wherein step (a3) further comprises applying a DC voltage of 15 volts for about two hours.

16. The method of claim 1 , wherein the nitridization step (b) is performed at 500-700° C.

17. The method of claim 9 , wherein the nitridization step (b) is performed at 500-600° C. for 25 minutes.

18. The method of claim 1 , wherein the nitridization step (b) is performed at an ammonia flow of 5-10 mL/minute.

19. The method of claim 1 , wherein the plurality of TiN nanocavities have an average diameter of 80 nm, average length of 180 nm, average wall thickness of about 20 nm and an average center-to-center distance of 100 nm, to define nanocontainers with a volume of about 750 zeptoliter.

20. The method of claim 1 , wherein at least a first of the TiN nanocavities comprises a titanium nitride nanofurnace disposed on a titanium film, the titanium nitride nanofurnace having an open top, a titanium nitride bottom, and a titanium nitride tubular middle portion extending from the open top to the titanium nitride bottom, and
wherein the method further comprises:
flowing a molecular gas in at least the titanium nitride nanofurnace;
applying light to the titanium nitride nanofurnace; and
using the titanium nitride nanofurnace to heat the molecular gas therein to bring about a chemical transformation in the first molecular gas.

Assignees

• Purdue Research Foundation
• Palacky Univ
• Univ Of Erlangen Nuremberg

Inventors

• Shalaev Vladimir M
• Kudyshev Zhaxylyk
• Boltasseva Alexandra
• Naldoni Alberto
• Kildishev Alexander
• Mascaretti Luca
• Kment Ŝtêphán
• Zbo{Circumflex Over (R)}Il Radek
• Yoo Jeong Eun
• Schmuki Patrik

Classifications

• G02B5/008

  Surface plasmon devices (diffractive gratings with a pitch less than or comparable to the wavelength G02B5/1809; surface plasmons in integrated optics G02B6/1226; optical analysis of materials by means of surface plasmons G01N21/553) · CPC title

• Y02E10/547

  Monocrystalline silicon PV cells · CPC title

• Y02E10/52

  PV systems with concentrators · CPC title

• C25D11/26 Primary

  of refractory metals or alloys based thereon · CPC title

• C01B21/076

  with titanium or zirconium {or hafnium} · CPC title