Electrodes for photovoltaic cells and methods for manufacture thereof

• US 20060110618A1
• Filed: 11/24/2004
• Published: 05/25/2006
• Est. Priority Date: 11/24/2004
• Status: Abandoned Application

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Iacovangelo, Charles Dominic, Manivannan, Venkatesan, Gui, John Yupeng, Morrison, William Arthur
• Application Number:
  US10/998,071
• Publication Number:
  US 20060110618A1
• Time in Patent Office: Days
• US Class Current: 428/566
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: C23C 16/405 of refractory metals or yttrium
• CPC Class Codes: C23C 16/56 After-treatment
• CPC Class Codes: H01G 9/2031 comprising titanium oxide, e.g. TiO2 H01G9/2036 takes precedence
• CPC Class Codes: H01G 9/2059 comprising an organic dye as the active light absorbing material, e.g. adsorbed on an electrode or dissolved in solution
• CPC Class Codes: Y02E 10/542 Dye sensitized solar cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10T 428/12146 Nonmetal particles in a component
• CPC Class Codes: Y10T 428/12153 Interconnected void structure [e.g., permeable, etc.]
• CPC Class Codes: Y10T 428/12167 Nonmetal containing

Abstract

Disclosed herein is an article comprising a substrate; and a columnar structure, wherein the columnar structure comprises a semi-conductor and is disposed upon the substrate in a manner wherein the longitudinal axis of the columnar structures is substantially perpendicular to the substrate. Disclosed herein is an electrode that comprises a substrate upon which is disposed an electron transport coating, wherein the electron transport coating comprises a columnar structure.

Claims

1. An article comprising:

a substrate; and

a columnar structure, wherein the columnar structure comprises a semi-conductor and is disposed upon the substrate in a manner wherein the longitudinal axis of the columnar structures is substantially perpendicular to the substrate.

2. The article of claim 1, wherein the substrate is optically transparent, porous and/or electrically conductive.

3. The article of claim 1, wherein the substrate is optically transparent, non-porous and/or electrically conductive.

4. The article of claim 1, wherein the substrate has a modulus of elasticity of less than or equal to about 10⁵ GPa at room temperature.

5. The article of claim 1, wherein the substrate comprises glass, polymers, metal foils or a combination thereof.

6. The article of claim 1, wherein the substrate comprises silica, alumina, zirconia, titania, a thermoplastic polymer, a thermosetting polymer, or a combination thereof.

7. The article of claim 1, wherein the semi-conductor is a metal oxide, and wherein the metal oxide is non-stoichiometric or stoichiometric.

8. The article of claim 1, wherein the semi-conductor is titanium oxide, and wherein the titanium oxide is non-stoichiometric or stoichiometric.

9. The article of claim 8, wherein the titanium dioxide has a crystalline structure.

10. The article of claim 1, wherein the columnar structure has an aspect ratio of greater than or equal to about 5.

11. The article of claim 1, wherein the columnar structure is disposed on the substrate in the form of a coating.

12. The article of claim 11, wherein the coating has a thickness of about 5 nanometers to about 1 millimeter.

13. The article of claim 11, wherein the coating has a surface area of greater than or equal to about 5 square meters per gram.

14. The article of claim 1, wherein the columnar structure has a cross-sectional area that is circular, rectangular, square or polygonal.

15. The article of claim 1, wherein the columnar structure comprises a metal oxynitride.

16. The article of claim 1, wherein the columnar structure has a minimum size of 5 nanometers when measured in a plane parallel to the surface of the substrate.

17. The article of claim 1, wherein the columnar structure has a length of greater than or equal to about 5 nanometers when measured in a plane perpendicular to the surface of the substrate.

18. The article of claim 1, wherein any two adjacent columnar structures are separated from each other by about 5 to about 500 nanometers.

19. The article of claim 1, wherein the columnar structure comprises alternating sections that are nanoporous and porous, and wherein the nanoporous sections have pores of about 1 to about 10 nanometers in diameter, and wherein the porous sections have pores greater than 10 nanometers in diameter.

20. The article of claim 19, wherein the nanoporous section has a thickness of less than or equal to about 0.2 micrometer, while the porous section has a thickness of less than or equal to about 0.2 micrometer, and wherein the thickness is measured in a direction perpendicular to the surface of the substrate.

21. The article of claim 1, wherein a columnar structure that is nanoporous is located next to a columnar structure that is porous.

22. The article of claim 1, wherein the columnar structure is formed in an expanding thermal plasma.

23. The article of claim 1, wherein the columnar structure comprises a rutile crystalline phase, an anatase crystalline phase, a brooklite phase or a combination comprising at least one of the foregoing crystalline phases.

24. The article of claim 1, wherein the columnar structure comprises an amorphous phase.

25. The article of claim 1, wherein the article is used in a photovoltaic cell.

43. The article of claim 1, wherein the columnar structure has an aspect ratio of greater than or equal to about 5.

26. An electrode comprising:

an electrically conductive substrate upon which is disposed an electron transport coating, wherein the electron transport coating comprises a columnar structure.

27. The electrode of claim 26, wherein the columnar structure has a cross-sectional area that is circular, rectangular, square or polygonal.

28. The electrode of claim 26, wherein the electron transport coating has a columnar structure that comprises a semi-conductor, a conductor, or a combination thereof.

29. The electrode of claim 28, wherein the semiconductor comprises a metal oxide and wherein the conductor comprises carbon nanotubes.

30. The electrode of claim 29, wherein the metal oxide is titanium oxide, and wherein the titanium oxide is non-stoichiometric or stoichiometric.

31. The electrode of claim 30, wherein the titanium dioxide has a crystalline structure, and wherein the crystalline structure comprises a rutile phase, an anatase phase, a brooklite phase, or a combination comprising at least one of the foregoing crystalline phases.

32. The electrode of claim 26, wherein the columnar structures have an aspect ratio of greater than or equal to about 2.

33. The electrode of claim 26, wherein the columnar structure is disposed on the electrically conductive substrate such that the longitudinal axis of the columnar structure is substantially perpendicular to the electrically conductive substrate.

34. The electrode of claim 26, wherein the coating has a thickness of about 5 nanometers to about 1 millimeter.

35. The electrode of claim 26, wherein the columnar structures are formed in an expanding thermal plasma.

36. The electrode of claim 26, wherein the electrically conductive substrate is optically transparent and/or porous.

37. The electrode of claim 26, wherein the electrically conductive substrate has a modulus of elasticity of less than or equal to about 10⁵ GPa at room temperature.

38. The electrode of claim 26, wherein the electrically conductive substrate comprises a supporting portion and an electrically conductive portion, wherein the electrically conductive portion is in contact with the columnar structure.

39. The electrode of claim 38, wherein the electrically conductive portion is a coating that comprises indium tin oxide, F-doped transparent oxides, conductive polymers, metallic thin films, metal foils, or a combination comprising at least one of the foregoing.

40. The electrode of claim 38, wherein the supporting portion comprises silica, alumina, zirconia, titania, a thermoplastic polymer, a thermosetting polymer, or a combination thereof.

41. The electrode of claim 38, wherein the supporting portion comprises polycarbonates, poly(meth)acrylates, polystyrenes, polyolefins, polyimides, polyetherimides, polyurethanes, polysiloxanes, epoxies, phenolics, or a combination thereof.

42. The electrode of claim 39, wherein the metal foil is aluminum, titanium, silver, platinum, zinc, molybdenum, tantalum, steel, invar, stainless steel, or a combination thereof.

44. The electrode of claim 26, wherein the columnar structure is disposed on the substrate in the form of a coating.

45. The electrode of claim 44, wherein the coating has a thickness of about 5 nanometers to about 1 millimeter.

46. The electrode of claim 44, wherein the coating has a surface area of greater than or equal to about 5 square meters per gram.

47. The electrode of claim 26, wherein the columnar structure has a cross-sectional area that is circular, rectangular, square or polygonal.

48. The electrode of claim 26, wherein the columnar structure comprises a metal oxynitride.

49. The electrode of claim 26, wherein the columnar structure has a minimum size of 5 nanometers when measured in a plane parallel to the plane of the substrate.

50. The electrode of claim 26, wherein the columnar structure has a length of greater than or equal to about 5 nanometers when measured in a plane perpendicular to the plane of the substrate.

51. The electrode of claim 26, wherein any two adjacent columnar structures are separated from each other by about 5 to about 500 nanometers.

52. The electrode of claim 26, wherein the columnar structure comprises alternating sections that are nanoporous and porous, and wherein the nanoporous sections have pores of about 1 to about 10 nanometers in diameter, and wherein the porous sections have pores greater than 10 nanometers in diameter.

53. The electrode of claim 52, wherein the nanoporous section has a thickness of less than or equal to about 0.2 micrometer, while the porous section has a thickness of less than or equal to about 0.2 micrometer, and wherein the thickness is measured in a direction perpendicular to the substrate.

54. The electrode of claim 26, wherein a columnar structure that is nanoporous is located next to a columnar structure that is porous.

55. The electrode of claim 26, wherein the columnar structure is formed in an expanding thermal plasma.

56. The electrode of claim 26, wherein the columnar structure comprises a rutile crystalline phase, an anatase crystalline phase, a brooklite phase or a combination comprising at least one of the foregoing crystalline phases.

57. The electrode of claim 26, wherein the columnar structure comprises an amorphous phase.

58. A photovoltaic cell comprising the electrode of claim 26.

59. A fuel cell comprising the electrode of claim 26.

60. A method comprising:

contacting a substrate with a plasma in an expanding thermal plasma generator, wherein the generator pressure is about 30 millitorr to about 300 millitorr; and

wherein the plasma comprises a reactive species and oxygen; and

disposing a semiconducting coating up on the substrate, wherein the semiconducting coating comprises a columnar microstructure.

61. The method of claim 60, wherein the semi-conductor coating is formed at a rate of greater than or equal to about 1 micrometer/minute.

62. The method of claim 60, wherein the reactant comprises titanium tetrachloride, titanium isopropoxide, titanium butoxide, titanium di-isopropoxide bis (2,4 pentanedionate), titanium (IV) ethoxide, titanium (IV) 2-ethylhexoate, titanium (IV) isobutoxide, titanium (IV) methoxide, or a combination comprising at least one of the foregoing precursors.

63. The method of claim 60, wherein the plasma further comprises an oxidant, and wherein the oxidant is oxygen, nitrous oxide, hydrogen peroxide, ozone, or water.

64. The method of claim 60, wherein the plasma comprises an argon plasma.

65. The method of claim 60, wherein the columnar structure comprises titanium dioxide.

66. The method of claim 60, further comprising sintering the substrate at a temperature of about 300 to about 500°

C.