Substrate for transparent electrodes

• US 7,396,580 B2
• Filed: 02/20/2003
• Issued: 07/08/2008
• Est. Priority Date: 02/26/2002
• Status: Expired due to Fees

• Current Assignee: Fujikura Limited
• Original Assignee: Fujikura Limited
• Inventors: Kawashima, Takuya, Tanabe, Nobuo, Matsui, Hiroshi, Okada, Kenichi
• Primary Examiner(s): Hendricks; Keith D.
• Assistant Examiner(s): FERGUSON, LAWRENCE D
• Application Number:
  US10/371,344
• Publication Number:
  US 20030170437A1
• Time in Patent Office: 1,965 Days
• Field of Search: 428/141, 428/142, 428/144, 428/212
• US Class Current: 428/212
• CPC Class Codes: C03C 17/3417 all coatings being oxide coatings
• CPC Class Codes: C03C 17/3452 comprising a fluoride
• CPC Class Codes: H01G 9/2031 comprising titanium oxide, e.g. TiO2 H01G9/2036 takes precedence
• CPC Class Codes: H01L 31/1884 Manufacture of transparent electrodes, e.g. TCO, ITO
• CPC Class Codes: H10K 30/82 Transparent electrodes, e.g. indium tin oxide [ITO] electrodes
• CPC Class Codes: H10K 77/10 Substrates, e.g. flexible substrates
• CPC Class Codes: Y02E 10/542 Dye sensitized solar cells
• CPC Class Codes: Y02E 10/549 Organic PV cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10T 428/24355 Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
• CPC Class Codes: Y10T 428/24364 with transparent or protective coating
• CPC Class Codes: Y10T 428/2438 Coated
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree

Abstract

One object of the present invention is to provide a transparent electrode substrate with an ITO film formed thereon, used for example as the transparent electrode plate in a dye sensitized solar cell, for which the electrical resistance does not increase even when exposed to high temperatures of 300° C. or higher. In order to achieve the object, the present invention provides a substrate for a transparent electrode, wherein two or more layers of different transparent conductive films are formed on a transparent substrate, and an upper layer transparent conductive film has a higher heat resistance than that of a lower layer transparent conductive film.

Claims

1. A substrate for a transparent electrode, comprising:

a transparent substrate; and

two or more layers of different transparent conductive films formed on said transparent substrate,

wherein an upper layer transparent conductive film has a higher heat resistance than that of a lower layer transparent conductive film, and

at least one of said layers other than an uppermost layer is an indium tin oxide film, having a thickness of 100-1000 nm,

and at least one transparent conductive film other than said indium tin oxide film comprises one or more transparent conductive films selected from the group consisting of fluorine doped tin oxide, antimony doped tin oxide, tin oxide, fluorine doped zinc oxide, aluminum doped zinc oxide, gallium doped zinc oxide, boron doped zinc oxide, and zinc oxide, having a thickness of 30-350 nm,

wherein said indium tin oxide layer is underneath and adjacent to said upper layer.

2. A substrate for a transparent electrode according to claim 1, wherein an increase in electrical resistance of said upper layer transparent conductive film on heating at 300 to 700°

C. is suppressed to an increase of no more than two times, and an increase in electrical resistance of said lower layer transparent conductive film on heating at 300°

C. or higher is 1.5 times or greater.

3. A substrate for a transparent electrode according to claim 1, wherein a transparent conductive film for which an increase in electrical resistance on heating at 300 to 700°

C. is suppressed to no more than two times is formed on top of said indium tin oxide film.

4. A substrate for a transparent electrode according to claim 2, wherein a transparent conductive film for which an increase in electrical resistance on heating at 300 to 700°

C. is suppressed to no more than two times is formed on top of said indium tin oxide film.

5. A substrate for a transparent electrode according to claim 3, wherein said transparent conductive film laminated on top of said indium tin oxide film is produced by a spray pyrolysis deposition method.

6. A substrate for a transparent electrode according to claim 1, wherein said transparent conductive film laminated on top of said indium tin oxide film is formed consecutively and immediately after formation of said indium tin oxide film.

7. A substrate for a transparent electrode according to claim 1, wherein the at least one transparent conductive film is fluorine doped tin oxide film.

8. A substrate for a transparent electrode according to claim 1, wherein the thickness of the at least one transparent conductive film is 150-350 nm.

9. A substrate for a transparent electrode according to claim 1, wherein said indium tin oxide film layer is free from oxidation deterioration.

10. A substrate for a transparent electrode according to claim 1, wherein the resistivity of said indium tin oxide film layer upon formation of said indium tin oxide film layer is the same as the resistivity of said indium tin oxide film layer after undergoing a heat treatment at 450°

C. for 1 hour.

11. A substrate for a transparent electrode according to claim 1, wherein the resistivity of said indium tin oxide film layer is between 1.8×

10 <sup>−

4</sup>Ω

·

cm and 2.1×

10 <sup>−

4</sup>Ω

·

cm.

12. A substrate for a transparent electrode according to claim 1, wherein said upper layer transparent conductive film comprises fluorine doped tin oxide.

13. A substrate for a transparent electrode according to claim 1, wherein said upper layer transparent conductive film comprises tin oxide.

14. A substrate for a transparent electrode according to claim 1, wherein said upper layer transparent conductive film comprises antimony doped tin oxide.

15. A substrate for a transparent electrode according to claim 12, wherein the resistivity of said indium tin oxide film layer is lower than the resistivity of said fluorine doped tin oxide film layer.