# US 2014/0154835 A1 · Method for fabricating solar cell

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- Number: US 2014/0154835 A1
- Document ID: US20140154835A1
- Status: Published application
- Kind: A1
- Application number: 13/929,067
- Filed: 2013-06-27
- Published: 2014-06-05
- Earliest claimed: 2012-12-03
- Assignees: Industrial Technology Research Institute
- Applicants: Industrial Technology Research Institute
- Inventors: Wei-Tse HSU
- Web page: https://patentgrep.com/patent/US20140154835A1

## CPC

- H10F 71/125: {The active layers comprising only Group II-VI materials, e.g. CdS, ZnS or CdTe}
- H10F 10/167: comprising Group I-III-VI materials, e.g. CdS/CuInSe2 [CIS] heterojunction photovoltaic cells
- H10F 77/126: {comprising only Group I-III-VI chalcopyrite materials, e.g. CuInSe2, CuGaSe2 or CuInGaSe2 [CIGS]}
- Y02E 10/541: CuInSe2 material PV cells
- Y02E 10/543: Solar cells from Group II-VI materials
- 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

The disclosure provides a method for fabricating a solar cell, including: providing a first substrate; forming a light absorption precursor layer on the first substrate; conducting a thermal process to the light absorption precursor layer to form a light absorption layer, wherein the light absorption layer includes a first light absorption layer and a second light absorption layer, and the first absorption layer is formed on the first substrate; forming a second substrate on the second light absorption layer; removing the first substrate to expose a surface of the first light absorption layer; forming a zinc sulfide (ZnS) layer on the surface of the first light absorption layer; and forming a transparent conducting oxide (TCO) layer on the zinc sulfide (ZnS) layer.

## Claims

### Claim 1

A method for fabricating a solar cell, comprising:
providing a first substrate;
forming a light absorption precursor layer on the first substrate;
conducting a thermal process to the light absorption precursor layer to form a light absorption layer, wherein the light absorption layer comprises a first light absorption layer and a second light absorption layer, and the first absorption layer is formed on the first substrate;
forming a second substrate on the second light absorption layer;
removing the first substrate to expose a surface of the first light absorption layer;
forming a zinc sulfide (ZnS) layer on the surface of the first light absorption layer; and
forming a transparent conducting oxide (TCO) layer on the zinc sulfide (ZnS) layer.

### Claim 2 (depends on 1)

The method for fabricating a solar cell as claimed in claim 1, wherein the light absorption layer comprises a copper indium gallium selenide (CIGS) compound.

### Claim 3 (depends on 1)

The method for fabricating a solar cell as claimed in claim 1, wherein the first light absorption layer comprises a copper gallium selenide (CGS) layer containing gallium-rich layer, and the second light absorption layer comprises a copper indium selenide (CIS) layer containing indium-rich layer.

### Claim 4 (depends on 1)

The method for fabricating a solar cell as claimed in claim 1, wherein the first substrate comprises glass, polymer substrate, metal substrate or combinations thereof.

### Claim 5 (depends on 1)

The method for fabricating a solar cell as claimed in claim 1, wherein forming the light absorption layer comprises a spin coating method, bar coating method, dip coating method, roll coating method, spray coating method, gravure coating method, ink jet printing method, slot coating method or blade coating method.

### Claim 6 (depends on 1)

The method for fabricating a solar cell as claimed in claim 1, wherein conducting the thermal process comprises:
placing the first substrate in an atmospheric environment containing Group VIA gas to conduct the thermal process.

### Claim 7 (depends on 6)

The method for fabricating a solar cell as claimed in claim 6, wherein the Group VIA gas comprises hydrogen selenide (H2Se), hydrogen sulfide (H2S), selenium (Se) vapor, sulfur (S) vapor, tellurium (Te) vapor or combinations thereof.

### Claim 8 (depends on 1)

The method for fabricating a solar cell as claimed in claim 1, wherein the thermal process is conducted at a temperature of about 450° C.-550° C.

### Claim 9 (depends on 1)

The method for fabricating a solar cell as claimed in claim 1, wherein the thermal process is conducted for about 10 minutes-60 minutes.

### Claim 10 (depends on 1)

The method for fabricating a solar cell as claimed in claim 1, wherein an average particle size of the second light absorption layer is larger than that of the first light absorption layer.

### Claim 11 (depends on 1)

The method for fabricating a solar cell as claimed in claim 1, wherein an average particle size of the first light absorption layer is about 50 nm-500 nm.

### Claim 12 (depends on 1)

The method for fabricating a solar cell as claimed in claim 1, wherein an average particle size of the second light absorption layer is about 1 μm-10 μm.

### Claim 13 (depends on 1)

The method for fabricating a solar cell as claimed in claim 1, wherein an energy gap of the second light absorption layer is smaller than that of the first light absorption layer.

### Claim 14 (depends on 1)

The method for fabricating a solar cell as claimed in claim 1, wherein the zinc sulfide (ZnS) layer further comprises oxygen (ZnS1−xOx, x=0−1).

### Claim 15 (depends on 1)

The method for fabricating a solar cell as claimed in claim 1, wherein the second substrate comprises glass, polymer substrate, metal substrate or combinations thereof.

### Claim 16 (depends on 15)

The method for fabricating a solar cell as claimed in claim 15, wherein the polymer substrate comprises polyimide (PI), poly(ethylene terephthalate) (PET), poly carbonate (PC), poly(methyl methacrylate) (PMMA) or combinations thereof.

### Claim 17 (depends on 1)

The method for fabricating a solar cell as claimed in claim 1, wherein the transparent conducting oxide (TCO) layer comprises indium tin oxide (ITO), indium oxide (In2O3), stannum oxide (SnO2), zinc oxide (ZnO), cadmium oxide(CdO), aluminum-doped zinc oxide (AZO), indium zinc oxide (IZO) or combinations thereof.

### Claim 18 (depends on 1)

The method for fabricating a solar cell as claimed in claim 1, wherein forming the second substrate on the second light absorption layer comprises:
coating a conductive glue on the second light absorption layer; and
forming the second substrate on the conductive glue.