Apparatus and methods for solar energy conversion using nanocoax structures

• US 20070047056A1
• Filed: 04/10/2006
• Published: 03/01/2007
• Est. Priority Date: 08/24/2005
• Status: Active Grant

• Current Assignee: Trustees of Boston College (Boston College)
• Original Assignee: Trustees of Boston College (Boston College)
• Inventors: Wang, Yang, Naughton, Michael, Kempa, Krzysztof, Ren, Zhifeng, Rybczynski, Jakub
• Granted Patent: US 7,754,964 B2
• Time in Patent Office: Days
• US Class Current: 359/245
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: G02B 6/107 Subwavelength-diameter waveguides, e.g. nanowires
• CPC Class Codes: H01L 31/035227 the quantum structure being quantum wires, or nanorods carbon nanotubes H10K85/211
• CPC Class Codes: H01L 31/07 the potential barriers being only of the Schottky type
• CPC Class Codes: H10K 30/10 comprising heterojunctions between organic semiconductors and inorganic semiconductors
• CPC Class Codes: H10K 30/50 Photovoltaic [PV] devices
• CPC Class Codes: H10K 85/221 Carbon nanotubes
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy

Abstract

An apparatus and method for solar conversion using nanocoax structures are disclosed herein. A nano-optics apparatus for use as a solar cell comprising a plurality of nano-coaxial structures comprising an internal conductor surrounded by a semiconducting material coated with an outer conductor; a film having the plurality of nano-coaxial structures; and a protruding portion of the an internal conductor extending beyond a surface of the film. A method of fabricating a solar cell comprising: coating a substrate with a catalytic material; growing a plurality of carbon nanotubes as internal cores of nanocoax units on the substrate; oxidizing the substrate; coating with a semiconducting film; and filling with a metallic medium that wets the semiconducting film of the nanocoax units.

Claims

1. A nano-optics apparatus for use as a solar cell comprising:

a plurality of nano-coaxial structures comprising an internal conductor surrounded by a semiconducting material coated with an outer conductor;

a film having the plurality of nano-coaxial structures; and

a protruding portion of the an internal conductor extending beyond a surface of the film.

2. The nano-optics apparatus of claim 1 wherein film is metallic.

3. The nano-optics apparatus of claim 1 wherein film is non-metallic.

4. The nano-optics apparatus of claim 1 wherein the protruding portion acts as a nano-antenna for receiving and transmitting an electromagnetic radiation into an interior of the nano-coaxial structures at a visible frequency.

5. The nano-optics apparatus of claim 4 wherein the nano-antenna compresses light into nanoscopic dimensions of the nano-coaxial structure.

6. The nano-optics apparatus of claim 1 wherein a convex indentation in the film around the protruding portion acts as a concentrator of an electromagnetic radiation.

7. The nano-optics apparatus of claim 6 wherein the concentrator compresses light at an entrance to the nano-coaxial structure.

8. The nano-optics apparatus of claim 1 wherein the nano-coaxial structures acts as a nano-coaxial transmission line (NCTL) for propagation of external radiation with a wavelength exceeding the perpendicular dimension of the internal conductor.

9. The nano-optics apparatus of claim 1 wherein plurality of nano-coaxial structures are carbon nanotubes.

10. The nano-optics apparatus of claim 1 wherein the semiconducting material is a dielectric material with a formula Al₂O₃.

11. The nano-optics apparatus of claim 1 wherein the plurality of nano-coaxial structures compresses the external radiation into a space between an internal electrode and an external electrode.

12. The nano-optics apparatus of claim 4 wherein the light is solar radiation.

13. A solar cell comprising:

a metallic film having a top surface, a bottom surface; and

a plurality of nano-coaxial structures comprising a metallic cylinder, filled with a dielectric material and having a central, concentric metallic core having a protruding portion extending beyond a top surface of the film.

14. The solar cell of claim 13 wherein the protruding portion is a nano-antenna for receiving and transmitting a radiation at a visible frequency.

15. The solar cell of claim 13 wherein the protruding portion compresses solar radiation into nanoscopic dimensions.

16. The solar cell of claim 13 wherein plurality of nano-coaxial structures are a nano-coaxial transmission lines (NCTL) for propagation of external solar radiation with a wavelength exceeding the perpendicular dimension of the core.

17. A method of fabricating a solar cell comprising:

coating a substrate with a catalytic material;

growing a plurality of carbon nanotubes as internal cores of nanocoax units on the substrate;

oxidizing the substrate;

coating with a semiconducting film; and

filling with a metallic medium.

18. The method of claim 17 wherein the substrate is flexible aluminum foil.

19. The method of claim 17 wherein the catalytic material is nickel.

20. The method of claim 17 wherein the metallic medium wets the semiconducting film of the nanocoax.

21. A method of fabricating a solar cell comprising:

coating a substrate with a chromium layer;

electrodepositing a catalytic transition metal on the coated substrate;

growing an array of carbon nanotubes (CNTs) on the coated substrate;

etching the chromium layer;

coating the coated substrate and the array of CNTs with a dielectric material; and

coating the coated substrate and the array of CNTs with a metal material.

22. The method of claim 21 further comprising applying a polymethylmethacrylate to the coated substrate.

23. The method of claim 21 further comprising polishing the coated substrate to expose the CNTs.