Front electrode including transparent conductive coating on patterned glass substrate for use in photovoltaic device and method of making same

• US 20080107799A1
• Filed: 04/26/2007
• Published: 05/08/2008
• Est. Priority Date: 11/02/2006
• Status: Active Grant

• Current Assignee: Guardian Glass LLC (KOCH Industries Incorporated)
• Original Assignee: Guardian Industries Corporation (KOCH Industries Incorporated)
• Inventors: Lu, Yiwei, den Boer, Willem
• Granted Patent: US 8,012,317 B2
• Time in Patent Office: Days
• US Class Current: 427/74
• CPC Class Codes: H01L 31/022425 for solar cells
• CPC Class Codes: H01L 31/022466 made of transparent conductive layers, e.g. TCO, ITO layers
• CPC Class Codes: H01L 31/0236 Special surface textures
• CPC Class Codes: H01L 31/02366 of the substrate or of a layer on the substrate, e.g. textured ITO/glass substrate or superstrate, textured polymer layer on glass substrate
• CPC Class Codes: H01L 31/048 Encapsulation of modules
• CPC Class Codes: H01L 31/0488 Double glass encapsulation, e.g. photovoltaic cells arranged between front and rear glass sheets
• CPC Class Codes: H01L 31/075 the potential barriers being only of the PIN type, e.g. amorphous silicon PIN solar cells
• CPC Class Codes: H01L 31/1884 Manufacture of transparent electrodes, e.g. TCO, ITO
• CPC Class Codes: Y02E 10/548 Amorphous silicon PV cells

Abstract

This invention relates to a photovoltaic device including an electrode such as a front electrode/contact. In certain example embodiments, the front electrode of the photovoltaic device includes a multi-layered transparent conductive coating which is sputter-deposited on a textured surface of a patterned glass substrate. In certain example embodiments, a maximum transmission area of the substantially transparent conductive front electrode is located under a peak area of a quantum efficiency (QE) curve of the photovoltaic device and a light source spectrum used to power the photovoltaic device.

Claims

1. A method of making a photovoltaic device, the method comprising:

providing a glass substrate;

etching and/or patterning at least one major surface of the glass substrate so as to form a textured surface of the glass substrate;

sputter-depositing a substantially conformal front electrode on the textured surface of the glass substrate, the front electrode being substantially conformal so that both major surfaces of the front electrode are textured in a manner similar to the textured surface of the glass substrate; and

using the substantially conformal front electrode formed on the textured surface of the glass substrate at a light incident side of a photovoltaic device.

2. The method of claim 1, further comprising determining a quantum efficiency (QE) curve for a photovoltaic device, and forming the front electrode in a manner so that a maximum transmission area of the front electrode is located under a peak area of the QE curve for the photovoltaic device.

3. The method of claim 2, further comprising forming the front electrode in a manner so that the maximum transmission area of the front electrode is located under a peak area of a combination of QE and a light source spectrum expected to be used to power the photovoltaic device.

4. The method of claim 3, wherein the light source spectrum is AM1.5.

5. The method of claim 2, further comprising forming the front electrode in a manner so that a transmission of the front electrode and the glass substrate taken together, into a semiconductor film of the photovoltaic device, is at least 80% in at least a substantial part of a wavelength range of from about 450-600 nm.

6. The method of claim 5, further comprising forming the front electrode in a manner so that the transmission of the front electrode and the glass substrate taken together is at least 85% in at least a substantial part of a wavelength range of from about 450-600 nm.

7. The method of claim 5, further comprising forming the front electrode in a manner so that the transmission of the front electrode and the glass substrate taken together is at least 87% in at least a substantial part of a wavelength range of from about 450-600 nm.

8. The method of claim 5, further comprising forming the front electrode in a manner so that the transmission of the front electrode and the glass substrate taken together is at least 88% in at least a substantial part of a wavelength range of from about 450-600 nm.

9. The method of claim 1, wherein the front electrode is multi-layered and comprises at least one layer that is conductive and substantially transparent.

10. The method of claim 9, wherein the transparent front electrode comprises, moving away from the glass substrate toward a semiconductor film of the photovoltaic device, at least a first substantially transparent conductive substantially metallic infrared (IR) reflecting layer comprising silver and/or gold, and a first transparent conductive oxide (TCO) film located between at least the IR reflecting layer and the semiconductor film.

11. The method of claim 10, wherein the first TCO film comprises one or more of zinc oxide, zinc aluminum oxide, tin oxide, indium-tin-oxide, and indium zinc oxide.

12. The method claim 10, wherein the substantially transparent front electrode further comprises a second substantially transparent conductive substantially metallic infrared (IR) reflecting layer comprising silver and/or gold, and wherein the first transparent conductive oxide (TCO) film is located between at least said first and second IR reflecting layers.

13. The method of claim 12, wherein the first and second IR reflecting layers each comprise silver.

14. The method of claim 1, wherein the glass substrate and front electrode taken together have an IR reflectance of at least about 45% in at least a substantial part of an IR wavelength range of from about 1400-2300 nm and/or 1000-2500 nm.

27. The method of claim 1, wherein the glass substrate has a haze value of from about 10-20%.

15. A method of making a photovoltaic device, the method comprising:

forming a substantially transparent conductive front electrode on a glass substrate;

determining a quantum efficiency (QE) curve for a photovoltaic device, and forming the substantially transparent front electrode in a manner so that a maximum transmission area of the substantially transparent front electrode is located under a peak area of the QE curve for the photovoltaic device; and

using the substantially transparent front electrode formed on the glass substrate at a light incident side of a photovoltaic device.

16. The method of claim 15, further comprising forming the front electrode in a manner so that the maximum transmission area of the front electrode is located under a peak area of a light source spectrum expected to be used to power the photovoltaic device.

17. The method of claim 16, wherein the light source spectrum is AM1.5.

18. The method of claim 15, further comprising forming the front electrode in a manner so that a transmission of the front electrode and the glass substrate taken together is at least 80% in at least a substantial part of a wavelength range of from about 450-600 nm.

19. The method of claim 18, further comprising forming the front electrode in a manner so that the transmission of the front electrode and the glass substrate taken together is at least 85% in at least a substantial part of a wavelength range of from about 450-600 nm.

20. The method of claim 15, wherein the front electrode comprises, moving away from the glass substrate toward a semiconductor film of the photovoltaic device, at least a first substantially transparent conductive substantially metallic infrared (IR) reflecting layer comprising silver and/or gold, and a first transparent conductive oxide (TCO) film located between at least the IR reflecting layer and the semiconductor film.

21. The method of claim 15, wherein at least one major surface of the glass substrate and both major surfaces of the front electrode are textured so as to have peaks and valleys defined therein.

22. A photovoltaic device comprising:

a front glass substrate;

a semiconductor film;

a substantially transparent conductive front electrode provided between at least the front glass substrate and the semiconductor film; and

wherein a maximum transmission area of the substantially transparent conductive front electrode is located under a peak area of a quantum efficiency (QE) curve of the photovoltaic device.

23. The photovoltaic device of claim 22, wherein the maximum transmission area of the front electrode is located under a peak area of QE and a light source spectrum expected to be used to power the photovoltaic device.

24. The photovoltaic device of claim 22, wherein a transmission of the front electrode and the front glass substrate taken together, into the semiconductor film, is at least 80% in at least a substantial part of a wavelength range of from about 450-600 nm.

25. The photovoltaic device of claim 24, wherein the transmission of the front electrode and the front glass substrate taken together is at least 85% in at least a substantial part of a wavelength range of from about 450-600 nm.

26. The photovoltaic device of claim 22, wherein at least one major surface of the front glass substrate and both major surfaces of the front electrode are textured so as to have peaks and valleys defined therein.

28. The photovoltaic device of claim 22, wherein the glass substrate has a haze value of from about 10-20%.