Thin film article and method for forming a reduced conductive area in transparent conductive films for photovoltaic modules

• US 8,525,019 B2
• Filed: 07/01/2010
• Issued: 09/03/2013
• Est. Priority Date: 07/01/2010
• Status: Expired due to Fees

• Current Assignee: First Solar Incorporated, First Solar Malaysia Sendirian Berhad (First Solar Incorporated)
• Original Assignee: PrimeStar Solar, Inc. (GE Aerospace)
• Inventors: Frey, Jonathan Mack, Feldman-Peabody, Scott Daniel
• Primary Examiner(s): Barton, Jeffrey T
• Assistant Examiner(s): Kang, Tae-Sik
• Application Number:
  US12/828,408
• Publication Number:
  US 20120000520A1
• Time in Patent Office: 1,160 Days
• Field of Search: 136/256
• 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 31/0463 characterised by special patterning methods to connect the PV cells in a module, e.g. laser cutting of the conductive or active layers
• CPC Class Codes: H01L 31/0465 comprising particular structures for the electrical interconnection of adjacent PV cells in the module H01L31/0463 takes precedence
• CPC Class Codes: H01L 31/073 comprising only AIIBVI compound semiconductors, e.g. CdS/CdTe solar cells
• CPC Class Codes: H01L 31/1884 Manufacture of transparent electrodes, e.g. TCO, ITO
• CPC Class Codes: Y02E 10/543 Solar cells from Group II-VI materials

Abstract

A method for forming a reduced conductive area in transparent conductive. The method includes providing a transparent, electrically conductive, chemically reducible material. A reducing atmosphere is provided and concentrated electromagnetic energy from an energy source is directed toward a portion of the transparent, electrically conductive, chemically reducible material to form a reduced conductive area. The reduced conductive area has greater electrical conductivity than the transparent, electrically conductive, chemically reducible material. A thin film article and photovoltaic module are also disclosed.

Claims

1. A method for forming a chemically reduced conductive area in a transparent conductive layer of a thin film photovoltaic device, the method comprising:

providing a superstrate having a first conductive layer thereon, wherein the first conductive layer comprises a transparent conductive oxide material;

depositing a first semiconductor layer on the first conductive layer;

depositing a second semiconductor layer on the first semiconductor layer;

forming a first scribe by selectively removing the first conductive layer, the first semiconductor layer, and the second semiconductor layer;

filling the first scribe with a dielectric material;

thereafter, exposing the superstrate to a reducing atmosphere;

in the reducing atmosphere, directing concentrated electromagnetic energy from an energy source toward the superstrate to form a second scribe having a chemically reduced conductive area defined in the first conductive layer, wherein the chemically reduced conductive area has greater electrical conductivity than the transparent conductive oxide material; and

thereafter, forming a second conductive layer on the second semiconductor layer and the chemically reduced conductive area.

2. The method of claim 1, wherein the transparent conductive oxide material is selected from the group consisting of SnO₂, In₂O₃, Cd₂SnO₄, ZnO, and combinations thereof.

3. The method of claim 1, wherein the transparent conductive oxide material comprises a cadmium tin oxide.

4. The method of claim 1, wherein the reducing atmosphere includes a gas selected from the group consisting of hydrogen, carbon monoxide, reforming gas and combinations thereof.

5. The method of claim 1, wherein providing the reducing atmosphere further comprises providing a gas additive.

6. The method of claim 5, wherein the gas additive is an organometallic gas.

7. The method of claim 6, wherein the organometallic gas is selected from the group consisting of tin tetrachloride, dimethyl cadmium, dimethyl zinc, and combinations thereof.

8. The method of claim 1, wherein the reducing atmosphere comprises hydrogen.

9. The method of claim 8, wherein the reducing atmosphere further comprises an organometallic gas.

10. The method of claim 8, wherein the reducing atmosphere further comprises tin tetrachloride.

11. The method of claim 8, wherein the reducing atmosphere further comprises dimethyl cadmium.

12. The method of claim 8, wherein the reducing atmosphere further comprises dimethyl zinc.

13. The method as in claim 1, further comprising:

after filling the first scribe with the dielectric material and prior to exposing the superstrate to the reducing atmosphere, depositing a first portion of the second conductive layer over the second semiconductor layer and the dielectric material in the first scribe.

14. The method as in claim 13, wherein the first portion of the second conductive layer comprises graphite.