Transparent Electrode

• US 20060228564A1
• Filed: 04/04/2006
• Published: 10/12/2006
• Est. Priority Date: 04/06/2005
• Status: Active Grant

• Current Assignee: Eclipse Energy Systems Inc.
• Original Assignee: Eclipse Energy Systems Inc.
• Inventors: Demiryont, Hulya
• Granted Patent: US 7,531,239 B2
• Time in Patent Office: Days
• US Class Current: 428/426
• CPC Class Codes: B32B 17/06 comprising glass as the main or only constituent of a layer, next to another layer of a specific material
• CPC Class Codes: C03C 17/36 at least one coating being a metal
• CPC Class Codes: C03C 17/3618 Coatings of type glass/inorganic compound/other inorganic layers, at least one layer being metallic
• CPC Class Codes: C03C 17/3644 the metal being silver
• CPC Class Codes: C03C 17/3655 the multilayer coating containing at least one conducting layer
• CPC Class Codes: C03C 17/3671 specially adapted for use as electrodes
• CPC Class Codes: C03C 17/3694 one layer having a composition gradient through its thickness
• CPC Class Codes: C03C 17/40 all coatings being metal coatings
• CPC Class Codes: C03C 2217/94 Transparent conductive oxide layers [TCO] being part of a multilayer coating
• CPC Class Codes: G02F 1/13439 characterised by their electrical, optical, physical properties; materials therefor; method of making
• CPC Class Codes: H01L 31/022466 made of transparent conductive layers, e.g. TCO, ITO layers
• CPC Class Codes: H01L 31/022475 composed of indium tin oxide [ITO]
• CPC Class Codes: Y10T 428/265 1 mil or less
• CPC Class Codes: Y10T 428/31659 With cellulosic layer

Abstract

An electrically conductive multilayer thin film structure and composition is transparent in both the visible and infrared portions of the spectrum. This multilayer film is readily deposited on a variety of substrates, including plastics, and survives such in service conditions as flexing, vibration, thermal cycling, thermal shock, ultraviolet exposure, and high humidity. The preferred films are also compatible with conventional photolithography processes.

Claims

1. ) A multilayer thin film having an optical transparency of at least fifty percent for all wavelengths between 400 nm and 25 microns and an electrical sheet resistance of no more than 100 ohms per square, the film comprising:

an optical-matching layer deposited directly on a supporting surface and having a thickness of not more than 60 nm;

a metallic conduction film deposited on the optical-matching layer having a thickness of at least three and not more than 60 nm; and

an overcoat layer deposited on the metallic conduction film having a thickness of at least 3 and not more than 120 nm.

2. ) The multilayer thin film of claim 1 further comprising a metallic electrode layer deposited on the overcoat layer, the metallic electrode layer having a thickness of at least 50 nm.

3. ) The multilayer thin film of claim 1 wherein the overcoat layer comprises an oxide of silicon and silicon and wherein the oxidation level of silicon in the overcoat layer increases with distance from the metallic conduction film.

4. ) The multilayer thin film of claim 1, wherein the supporting surface comprises a portion of a substrate transparent for at least a selected band of wavelengths lying between 400 nm and 25 microns, the substrate comprising one of glass, plastic, silicon, germanium, zinc sulfide, and zinc selenide.

5. ) The multilayer thin film of claim 1 wherein the supporting surface comprises a surface of a flexible polymeric substrate.

6. ) The multilayer thin film of claim 1 wherein the supporting surface comprises a substrate having sequentially layered thereon a first electrode, a first electrochromic active layer, an electrolyte layer, and a second electrochromic active layer, whereby the combination of the multilayer thin film and the supporting surface comprises an electrochromic device.

7. ) The multilayer thin film of claim 1, wherein the metallic conduction film is a multi-layer film comprising:

a first metallic layer comprising one of silver, gold, copper or and aluminum and having a thickness of at least three and not more than 60 nm;

a semiconductor layer comprising one of silicon, germanium, and a TCO and having a thickness of not more than ten nm; and

a second metallic conduction layer comprising one of silver, gold, copper or and aluminum and having a thickness of at least three and not more than 60 nm; and

wherein the overcoat layer comprises silicon and has a thickness of at least three and not more than 120 nm.

8. ) The multilayer thin film of claim 1 wherein the optical-matching layer comprises silicon.

9. ) The multilayer thin film of claim 1 wherein the optical-matching layer comprises germanium.

10. ) The multilayer thin film of claim 1 wherein the optical-matching layer comprises a TCO.

11. ) The multilayer thin film of claim 1 wherein the optical-matching layer comprises a zinc chalcogenide.

12. ) The multilayer thin film of claim 1 wherein the metallic conduction film comprises one of silver, gold, copper and aluminum.

13. ) The multilayer thin film of claim 1 wherein the overcoat layer comprises one of silicon and germanium.

14. ) A multilayer thin film having an optical-transparency of at least 50% for at least a selected band of wavelengths between 400 nm and 25 microns and an electrical sheet resistance of no more than 100 Ohm/sq, the multilayer film comprising:

an optical-matching layer deposited directly on a supporting surface;

a metallic conduction layer deposited on the optical-matching layer, the metallic conduction layer having an optical transparency of at least 75% for the selected band of wavelengths and an electrical sheet resistance not more than 5 Ohm/sq; and

an overcoat layer deposited on the optical-matching layer.

15. ) The multilayer thin film of claim 14 wherein the optical-matching layer comprises one of silicon, germanium, a TCO, and a zinc chalcogenide.

16. ) The multilayer thin film of claim 14 wherein the metallic conduction layer comprises one of silver, gold, and aluminum.

17. ) The multilayer thin film of claim 14 wherein the overcoat layer comprises one of silicon, germanium, and a TCO.

18. ) A transparent thin film conductor deposited on a substrate, the thin film conductor comprising:

an optical-matching layer deposited directly on the substrate;

a first metallic conductive layer comprising a first selected metal deposited directly on the optical-matching layer, the first selected metal characterized by a first opacity threshold thickness wherein all films having a thickness greater than the first opacity threshold thickness are opaque to visible and infrared radiation, the first metallic conductive layer having a thickness selected to be at least one half of the first opacity threshold thickness;

a semiconductor layer deposited on the first metallic conduction layer;

a second metallic conductive layer comprising a second selected metal deposited directly on the semiconductor layer, the second selected metal characterized by a second opacity threshold thickness wherein all films having a thickness greater than the second opacity threshold thickness are opaque to visible and infrared radiation, the second metallic conductive layer having a thickness selected to be at least one half of the second opacity threshold thickness; and

an overcoat layer deposited on the second metallic layer.

19. ) The transparent thin film conductor of claim 18 wherein at least one of the first and second selected metals comprises silver.

20. ) The transparent thin film conductor of claim 18 wherein the semiconductor layer comprises silicon having a thickness of at least zero nm and not more than 250 nm.

21. ) The transparent thin film conductor of claim 18 wherein the adhesion-enhancing, optical-matching layer comprises silicon.

22. ) The transparent thin film conductor of claim 18 wherein the overcoat layer comprises silicon.

23. ) The transparent thin film conductor of claim 18 wherein the optical-matching layer, the semiconductor layer, and the overcoat layer all comprise silicon, and wherein the metallic conduction layers both comprise silver.

24. ) The transparent thin film conductor of claim 18, wherein the substrate is transparent for at least a selected band of wavelengths lying between 400 nm and 25 microns, the substrate comprising one of glass, plastic, silicon, germanium, zinc sulfide and zinc selenide.

25. ) A transparent multilayer thin film conductor deposited on an insulating substrate, the thin film conductor comprising:

two metallic conductive layers consisting of substantially the same metal, each of the layers having a common metal thickness measured by a chosen thickness measurement method, the common metal thickness selected so that each of the layers is transparent, the common metal thickness characterized by a nominal sheet resistance measured on a test film of the same metal deposited on an insulating substrate by the selected deposition method and having the common metal thickness when measured by the chosen thickness measurement method;

a semiconductor layer deposited by the selected method between the two metallic conductive layers, the semiconductor layer having a semiconductor layer thickness selected so that the semiconductor layer is transparent and so that a sheet resistance of the multilayer thin film conductor is less than one half of the nominal sheet resistance.

26. ) The transparent multilayer thin film conductor of claim 25 further comprising an optical-matching layer deposited directly on the insulating substrate and having a first of the two metallic conductive layers deposited directly thereon.

27. ) The transparent multilayer thin film conductor of claim 25 wherein the same metal used for the two metallic conductor layers comprises one of silver, gold, copper and aluminum.

28. ) The transparent multilayer thin film conductor of claim 25 wherein the semiconductor layer comprises silicon.

29. ) The transparent multilayer thin film conductor of claim 25 wherein the substrate is transparent for at least a selected band of wavelengths lying between 400 nm and 25 microns, the substrate comprising one of glass, plastic, silicon, germanium, zinc sulfide and zinc selenide.