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

• US 20080178932A1
• Filed: 12/03/2007
• Published: 07/31/2008
• Est. Priority Date: 11/02/2006
• Status: Abandoned Application

• Current Assignee: Guardian Glass LLC (KOCH Industries Incorporated)
• Original Assignee: Guardian Industries Corporation (KOCH Industries Incorporated)
• Inventors: Lu, Yiwei, Den Boer, Willem
• Application Number:
  US11/987,664
• Publication Number:
  US 20080178932A1
• Time in Patent Office: Days
• US Class Current: 136/256
• CPC Class Codes: H01L 31/022466 made of transparent conductive layers, e.g. TCO, ITO layers
• CPC Class Codes: H01L 31/022483 composed of zinc oxide [ZnO]
• 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 31/1884 Manufacture of transparent electrodes, e.g. TCO, ITO
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy

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) and/or QEx (photon flux of solar radiation) curve of the photovoltaic device and a light source spectrum used to power the photovoltaic device. In certain example embodiments, the front electrode includes a transparent conductive layer of or including one or more of (i) titanium zinc oxide doped with aluminum and/or niobium, and/or (ii) titanium niobium oxide.

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 wherein the front electrode comprises a first conductive layer and a second conductive layer, the second conductive layer being located between at least the first conductive layer and a semiconductor film, and wherein the second conductive layer comprises titanium zinc oxide doped with aluminum and/or niobium; and

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

2. The method of claim 1, wherein the titanium zinc oxide is doped with from about 0.01 to 10% Al and/or Nb.

3. The method of claim 1, wherein the titanium zinc oxide is doped with from about 0.02 to 7% Al and/or Nb.

4. The method of claim 1, wherein the titanium zinc oxide is doped with from about 0.1 to 5% Al and/or Nb.

5. The method of claim 1, further comprising determining a quantum efficiency (QE) and/or QEx (photon flux of solar radiation) 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 and/or QEx (photon flux of solar radiation) curve for the photovoltaic device.

6. The method of claim 5, 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.

7. The method of claim 6, wherein the light source spectrum is AM1.5.

8. The method of claim 5, 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.

9. The method of claim 8, 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.

10. The method of claim 8, 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.

11. 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 wherein the front electrode comprises a first conductive layer and a second conductive layer, the second conductive layer being located between at least the first conductive layer and a semiconductor film, and wherein the second conductive layer comprises titanium niobium oxide; and

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

12. The method of claim 11, wherein the layer comprising titanium niobium oxide includes from about 0.01 to 10% Nb, and may optionally further include aluminum.

13. The method of claim 11, wherein the layer comprising titanium niobium oxide includes from about 0.1 to 5% Nb.

14. The method of claim 11, further comprising determining a quantum efficiency (QE) and/or QEx (photon flux of solar radiation) 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 and/or QEx (photon flux of solar radiation) curve for the photovoltaic device.

15. The method of claim 14, 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.

16. The method of claim 15, wherein the light source spectrum is AM1.5.

17. 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;

wherein a maximum transmission area of the substantially transparent conductive front electrode is located under a peak area of a quantum efficiency (QE) and/or QEx (photon flux of solar radiation) curve of the photovoltaic device; and

wherein the front electrode comprises a first conductive layer and a second conductive layer, the second conductive layer being located between at least the first conductive layer and the semiconductor film, and wherein the second conductive layer comprises one or both of;

(i) titanium zinc oxide doped with aluminum and/or niobium; and

/or (ii) titanium niobium oxide.

18. The photovoltaic device of claim 17, 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.

19. The photovoltaic device of claim 17, 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.

20. The photovoltaic device of claim 17, 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.

21. The photovoltaic device of claim 17, 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.