# US 2013/0153031 A1 · Photovoltaic device with an anti-reflective surface and methods of manufacturing same

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- Number: US 2013/0153031 A1
- Document ID: US20130153031A1
- Status: Published application
- Kind: A1
- Application number: 13/717,789
- Filed: 2012-12-18
- Published: 2013-06-20
- Earliest claimed: 2011-12-20
- Assignees: First Solar, Inc.
- Inventors: Yu Yang; Jigish Trivedi
- Web page: https://patentgrep.com/patent/US20130153031A1

## CPC

- H10F 71/138: {Manufacture of transparent electrodes, e.g. transparent conductive oxides [TCO] or indium tin oxide [ITO] electrodes}
- H10F 77/315: {the coatings being antireflective or having enhancing optical properties}
- H10F 77/488: {Reflecting light-concentrating means, e.g. parabolic mirrors or concentrators using total internal reflection}
- H10F 77/707: {of the substrates or of layers on substrates, e.g. textured ITO layer on a glass substrate}
- Y02E 10/52: PV systems with concentrators
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A photovoltaic device comprising a substrate which has a porous first surface and a transparent conductive oxide layer located on a second surface opposite the first surface. A method of manufacturing the device is also described.

## Claims

### Claim 1

A photovoltaic device comprising:
a substrate comprising:
a porous first surface as an antireflective surface;
a second surface opposite the first surface; and
a transparent conductive oxide layer on the side of the second surface of the substrate.

### Claim 2 (depends on 1)

The photovoltaic device of claim 1, wherein the porous first surface comprises an etched substrate surface.

### Claim 3 (depends on 1)

The photovoltaic device of claim 1, wherein the substrate comprises glass.

### Claim 4 (depends on 1)

The photovoltaic device of claim 1, wherein the porous first surface is alkaline depleted.

### Claim 5 (depends on 1)

The photovoltaic device of claim 1, further comprising a protective layer adjacent to the transparent conductive oxide layer, wherein the protective layer comprises a material that is resistant to etching.

### Claim 6 (depends on 5)

The photovoltaic device of claim 5, wherein the protective layer comprises a polymer material.

### Claim 7 (depends on 1)

The photovoltaic device of claim 1, wherein the porous first surface reflects about 1% to about 4% less light having a wavelength from about 350 nm to about 1,000 nm, compared to a substrate which has a non-porous surface.

### Claim 8 (depends on 1)

The photovoltaic device of claim 1, further comprising a semiconductor material on the side of the second surface of the substrate.

### Claim 9 (depends on 8)

The photovoltaic device of claim 8, wherein the semiconductor material comprises a semiconductor window layer and a semiconductor absorber layer adjacent to the semiconductor window layer.

### Claim 10 (depends on 9)

The device of claim 9, wherein the semiconductor absorber layer comprises cadmium telluride.

### Claim 11 (depends on 9)

The device of claim 9, wherein the semiconductor absorber layer comprises copper indium gallium (di)selenide.

### Claim 12 (depends on 9)

The device of claim 9, wherein the semiconductor window layer comprises cadmium selenide.

### Claim 13 (depends on 1)

The photovoltaic device of claim 1, wherein the porous first surface comprises a porous skeletonized portion that is positioned adjacent to a substantially non-porous body of the substrate.

### Claim 14 (depends on 1)

The photovoltaic device of claim 1, wherein the transparent conductive oxide is resistant to etching.

### Claim 15 (depends on 13)

The photovoltaic device of claim 13, wherein the transparent conductive oxide layer comprises tin oxide.

### Claim 16

An article of manufacture comprising:
a substrate with a first etchable surface and second surface;
a transparent conductive oxide layer adjacent to the second surface; and
an etchant resistant protective layer adjacent to the transparent conductive oxide layer.

### Claim 17 (depends on 16)

The article of claim 16, wherein the substrate comprises glass.

### Claim 18 (depends on 16)

The article of claim 16, wherein the protective layer comprises a polymer material.

### Claim 19 (depends on 18)

The article of claim 18, wherein the polymer material is dissolvable in a solvent.

### Claim 20 (depends on 19)

The article of claim 19, wherein the polymer material is selected from the group consisting of polyethylene and polypropylene.

### Claim 21

A method for manufacturing a photovoltaic module comprising:
providing a light transmitting sheet, the sheet comprising:
a first surface configured to be illuminated, and
a second surface opposite the first surface;
forming a transparent conductive oxide layer adjacent to the second surface; and
contacting the first surface of the sheet with an etchant, thereby making at least a portion of the first surface porous.

### Claim 22 (depends on 21)

The method of claim 21, wherein the light transmitting sheet comprises glass.

### Claim 23 (depends on 21)

The method of claim 21, wherein the step of contacting the first surface of the light transmitting sheet with an etchant occurs prior to the step of forming a transparent conductive oxide layer.

### Claim 24 (depends on 21)

The method of claim 21, wherein the step of forming a transparent conductive oxide layer occurs prior to the step of contacting the light transmitting sheet with an etchant.

### Claim 25 (depends on 24)

The method of claim 24, further comprising forming a protective layer covering at least part of the transparent conductive oxide prior to contacting the light transmitting sheet with the etchant.

### Claim 26 (depends on 21)

The method of claim 21, wherein the porous first surface portion of the light transmitting sheet reflects about 1% to about 4% less light having a wavelength in the range of about 350 nm to about 1000 nm incident on the porous first surface portion, compared to the light transmitting sheet without a porous surface.

### Claim 27 (depends on 21)

The method of claim 21, wherein contacting the first surface of the sheet with the etchant comprises immersing at least part of the light transmitting sheet in a container containing the etchant.

### Claim 28 (depends on 27)

The method of claim 27, wherein immersing at least part of the light transmitting sheet in a container containing the etchant comprises conveying the sheet through a container containing the etchant.

### Claim 29 (depends on 27)

The method of claim 27 wherein the transparent conductive oxide layer is not immersed in the container containing the etchant.

### Claim 30 (depends on 27)

The method of claim 27, wherein the second surface of the sheet is not immersed in the container containing the etchant

### Claim 31 (depends on 21)

The method of claim 21, wherein contacting the first surface of the light transmitting sheet with the etchant comprising spraying the light transmitting sheet with an etchant.

### Claim 32 (depends on 21)

The method of claim 21, further comprising forming a protective layer adjacent to the transparent conductive oxide layer before contacting the first surface of the light transmitting sheet with the etchant.

### Claim 33 (depends on 32)

The method of claim 32, further comprising removing the protective layer after contacting the light transmitting sheet with the etchant.

### Claim 34 (depends on 23)

The method of claim 23, wherein the etchant comprises a fluorine-containing compound.

### Claim 35 (depends on 34)

The method of claim 34, wherein the etchant comprises hydrogen fluoride.

### Claim 36 (depends on 34)

The method of claim 34, wherein the etchant comprises fluorosilicic acid.

### Claim 37 (depends on 13)

The method of claim 13, further comprising cleaning the light transmitting sheet after the step of contacting the first surface of the light transmitting sheet with the etchant.