Light Transmittance Optimizing Coated Glass Article for Solar Cell and Method for Making

• US 20090155619A1
• Filed: 08/24/2006
• Published: 06/18/2009
• Est. Priority Date: 08/30/2005
• Status: Active Grant

• Current Assignee: Pilkington Group Limited, Pilkington North America Incorporated (Pilkington PLC)
• Original Assignee: Pilkington Group Limited
• Inventors: Nichol, Gary, Varansi, Srikanth, Nelson, Douglas M.
• Granted Patent: US 7,968,201 B2
• Time in Patent Office: Days
• US Class Current: 428/631
• CPC Class Codes: H01L 31/02168 the coatings being antireflective or having enhancing optical properties for the solar cells
• CPC Class Codes: H01L 31/03762 including only elements of Group IV of the Periodic Table
• CPC Class Codes: Y02E 10/548 Amorphous silicon PV cells
• CPC Class Codes: Y10T 428/12604 Film [e.g., glaze, etc.]
• CPC Class Codes: Y10T 428/265 1 mil or less

Abstract

A multi-layer thin film stack, particularly suitable as a component of a solar cell, is deposited on a transparent dielectric substrate. The multi-layer film stack comprises a transparent electrically conductive metal oxide layer deposited over the dielectric substrate, the conductive metal oxide layer having a refractive index less than 2.0, a light transmittance optimizing interlayer having a refractive index between 2.3 and 3.5, deposited over the electrically conductive metal oxide layer, and a silicon layer having a refractive index of at least 4.5 deposited over the light transmittance optimizing interlayer. The film stack can be deposited by any suitable method, but deposition of each of these layers by atmospheric chemical vapor deposition is preferred.

Claims

1. A coated article suitable for use as a component of a solar cell comprising:

a transparent dielectric substrate;

a transparent, electrically conductive metal oxide layer, having a refractive index less than 2.0, deposited over the dielectric substrate;

a light transmittance optimizing interlayer deposited over the conductive metal oxide layer, the light transmittance optimizing interlayer having a refractive index between 2.3 and 3.5; and

a silicon layer having a refractive index of at least 4.5 deposited over the light transmittance optimizing interlayer.

2. The coated glass article defined in claim 1, wherein the electrically conductive layer comprises a fluorine doped metal oxide.

3. The coated glass article defined in claim 1, wherein the light transmittance optimizing interlayer comprises a metal oxide layer.

4. The coated glass article defined in claim 3, wherein the light transmittance optimizing interlayer comprises an oxide of titanium.

5. The coated glass article defined in claim 1, wherein the silicon layer comprises amorphous silicon.

6. The coated glass article defined in claim 1, further comprising a color suppression film interposed between the dielectric substrate and the electrically conductive layer.

7. The coated glass article defined in claim 6, wherein the color suppression film comprises one chosen from the group consisting of:

a single metal oxide layer, a metal oxide layer and a silica layer, and a gradient layer.

8. The coated glass article defined in claim 6, wherein the color suppression film comprises a tin oxide layer having a thickness of 250-600 Å

, and a silica layer having a thickness of 250-350 Å

.

9. The coated glass article defined in claim 4, wherein the light transmittance optimizing film comprises a titanium oxide layer having an average thickness of 300-600 Å

.

10. The coated glass article defined in claim 9, wherein the light transmittance optimizing film stack comprises a titanium oxide layer having an average thickness of 450-500 Å

.

11. The coated glass article defined in claim 2, wherein the doped metal oxide layer comprises fluorine-doped tin oxide having a thickness of 5,000-7,500 Å

.

12. The coated glass article defined in claim 3, wherein the light transmittance optimizing interlayer has a refractive index between 2.3 and 3.0.

13. The coated glass article defined in claim 2, wherein the doped metal oxide layer comprises fluorine-doped tin oxide having a thickness of 3000-5,500 Å

.

14. The coated glass article defined in claim 1, wherein the silicon layer has a refractive index of at least 5.0.

15. The coated glass article defined in claim 1, wherein the electrically conductive layer comprises tin doped indium oxide

16. A method of forming a coated article suitable for use as a component of a solar cell, comprising:

providing a heated dielectric substrate;

depositing over the substrate a transparent, electrically conductive metal oxide layer having a refractive index less than 2.0;

depositing a light transmittance optimizing interlayer over the conductive metal oxide layer, the light transmittance optimizing interlayer having a refractive index between 2.3 and 3.5; and

depositing a silicon layer over the light transmittance optimizing interlayer, the silicon layer having a refractive index of at least 4.5.

17. The method defined in claim 16, wherein each layer is deposited online during the gloat glass manufacturing process.

18. The method defined in claim 16, wherein each layer is deposited by atmospheric chemical vapor deposition.

19. A transparent, coated glass article suitable for use as a component of a solar cell comprising:

a transparent dielectric substrate;

a transparent, electrically conductive metal oxide layer having a refractive index less than 2.0 deposited over the dielectric substrate;

a light transmittance optimizing interlayer deposited over the conductive metal oxide layer, the light transmittance optimizing interlayer having a refractive index between 2.3 and 3.5; and

a silicon layer having a refractive index of at least 4.5 deposited over the light transmittance optimizing interlayer;

wherein the coated article has a glass side reflectance of 5.2 to 8.0.

20. A coated article suitable for use as a component of a solar cell comprising:

a transparent dielectric substrate;

a transparent, electrically conductive metal oxide layer, having a refractive index less than 2.0, deposited over the dielectric substrate;

a light transmittance optimizing interlayer deposited directly on the conductive metal oxide layer, the light transmittance optimizing interlayer having a refractive index between 2.3 and 3.5; and

a silicon layer having a refractive index of at least 4.5 deposited over the light transmittance optimizing interlayer.

21. A coated article suitable for use as a component of a solar cell comprising:

a transparent dielectric substrate;

a transparent, electrically conductive tin oxide layer, having a refractive index less than 2.0, deposited over the dielectric substrate;

a light transmittance optimizing interlayer deposited directly on the conductive tin oxide layer, the light transmittance optimizing the interlayer comprising an oxide of titanium deposited at a thickness of 300 Å

-600 Å

; and

a silicon layer having a refractive index of at least 4.5 deposited over the light transmittance optimizing interlayer.

22. A coated article suitable for use as a component of a solar cell comprising:

a transparent glass substrate;

a transparent, electrically conductive tin oxide layer, having a refractive index less than 2.0, deposited over the dielectric substrate;

a light transmittance optimizing interlayer deposited directly on the conductive tin oxide layer, the light transmittance optimizing interlayer comprising TiO₂ deposited at a thickness of 450 Å

-500 Å

; and

a silicon layer having a refractive index of at least 4.5 deposited over the light transmittance optimizing interlayer.