Solar cell and method fabricating the same

Patent metadata

Field	Value
Publication number	US-8987585-B2
Application number	US-201013379557-A
Country	US
Kind code	B2
Filing date	Oct 28, 2010
Priority date	Oct 28, 2009
Publication date	Mar 24, 2015
Grant date	Mar 24, 2015

Abstract

A solar cell according to an embodiment includes a pattern layer arranged on a substrate and including a uneven pattern; a back electrode arranged on the pattern layer; a light absorption layer arranged on the back electrode; a buffer layer on the light absorption layer; and a front layer arranged on the buffer layer.
The method fabricating a solar cell according to an embodiment includes forming a pattern layer including a uneven pattern on a substrate; forming a back electrode on the pattern layer; forming a light absorption layer on the back electrode; forming a buffer layer on the light absorption layer; and forming a front electrode on the buffer layer.

First claim

What is claimed is:

1. A solar cell, comprising:
a pattern layer arranged on a substrate and including an uneven pattern on the entire surface of the substrate, wherein the pattern layer is formed of a different material than the substrate is;
a back electrode arranged on the pattern layer;
a light absorption layer arranged on the back electrode, wherein a portion of the light absorption layer is formed on and in direct physical contact with the uneven pattern of the pattern layer;
a buffer layer arranged on the light absorption layer; and
a front electrode arranged on the buffer layer;
wherein the pattern layer comprises a resin material comprising at least one material selected from the group consisting of epoxy, epoxy melanin, acrylic, and urethane resin,
wherein the pattern layer comprises a flat bottom surface;
wherein the entire flat bottom surface of the pattern layer has a uniform distance from an entire top surface of the light absorption layer;
wherein the pattern layer comprises grooves and protrusions in the uneven pattern on a top surface thereof, and
wherein the portion of the light absorption layer in direct physical contact with the uneven pattern of the pattern layer is in direct physical contact with at least one groove and at least one protrusion of the uneven pattern.

2. The solar cell according to claim 1 , wherein a width of the grooves is from 100 nm to 300 nm, a width of the protrusions is from 100 nm to 200 nm, a height of the grooves and protrusions is from 100 nm to 300 nm, and a period of the uneven pattern including the grooves and the protrusions is from 200 nm to 500 nm.

3. The solar cell according to claim 1 , wherein looking into the substrate, the pattern layer and the back electrode, when a is a distance from the top surface of the uneven pattern, that is, the top surface of the protrusions to the surface of the back electrode, b is the height of the grooves, c is the height of the grooves, and d is a thickness from the bottom surface of the grooves to the substrate in the pattern layer, a conditional expression of (a+b)=W(c+d) is satisfied, where W has the value of from 0.17 to 0.43.

4. The solar cell according to claim 1 , looking into the pattern layer, when c is the height of the grooves, and d is the thickness from the bottom surface of the grooves to the substrate in the pattern layer, the conditional expression of (c)=X(d) is satisfied, where X has the value of from 0.03 to 0.15.

5. The solar cell according to claim 1 , looking into the substrate and the pattern layer, when d is the thickness from the bottom surface of the grooves to the substrate in the pattern layer, and e is the thickness of the substrate, the conditional expression of (d)=Y(e) is satisfied, where Y has the value of from 0.04 to 0.12.

6. The solar cell according to claim 1 , wherein looking into the pattern layer, when f is the width of the grooves, and g is the width of the protrusions, the conditional expression of (f)=Z(g) is satisfied, where Z has the value of from 1 to 2.

7. The solar cell according to claim 1 , wherein the side in which the back electrode contacts the pattern layer is formed to have a concavo-convex pattern corresponding to the uneven pattern of the pattern layer, and the top surface of the back electrode is formed in parallel with the substrate.

8. The solar cell according to claim 1 , wherein the width of the uneven pattern is narrowed from the substrate toward the back electrode.

9. A method of fabricating a solar cell, comprising:
forming a pattern layer including an uneven pattern on a substrate, wherein the pattern layer is formed of a different material than the substrate is;
forming a back electrode on the pattern layer;
forming a light absorption layer on the back electrode, wherein a portion of the light absorption layer is formed on and in direct physical contact with the uneven pattern of the pattern layer;
forming a buffer layer on the light absorption layer; and
forming a front electrode on the buffer layer;
wherein the pattern layer comprises a resin material comprising at least one material selected from the group consisting of epoxy, epoxy melanin, acrylic, and urethane resin;
wherein the pattern layer comprises a flat bottom surface;
wherein the entire flat bottom surface of the pattern layer has a uniform distance from an entire top surface of the light absorption layer;
wherein the pattern layer comprises grooves and protrusions in the uneven pattern on a top surface thereof, and
wherein the portion of the light absorption layer in direct physical contact with the uneven pattern of the pattern layer is in direct physical contact with at least one groove and at least one protrusion of the uneven pattern.

10. The method of fabricating a solar cell according to claim 9 , wherein the forming the pattern layer includes forming a resin layer on the substrate; and forming the pattern layer formed with the uneven pattern by applying a molding process using mold to the resin layer and simultaneously applying UV hardening process.

11. The method of fabricating a solar cell according to claim 9 , wherein the width of the grooves is from 100 nm to 300 nm, the width of the protrusions is from 100 nm to 200 nm, the height of the grooves and protrusions is from 100 nm to 300 nm, and a period of the uneven pattern including the grooves and the protrusions is from 200 nm to 500 nm.

12. The method of fabricating a solar cell according to claim 9 , wherein looking into the substrate, the pattern layer and the back electrode, when a is a distance from the top surface of the uneven pattern, that is, the top surface of the protrusions to the surface of the back electrode, b is a height of the grooves, c is a height of the grooves, and d is a thickness from the bottom surface of the grooves to the substrate in the pattern layer, a conditional expression of (a+b)=W(c+d) is satisfied, where W has the value of from 0.17 to 0.43.

13. The method of fabricating a solar cell according to claim 9 , looking into the pattern layer, when c is a height of the grooves, and d is a thickness from the bottom surface of the grooves to the substrate in the pattern layer, a conditional expression of (c)=X(d) is satisfied, where X has the value of from 0.03 to 0.15.

14. The method of fabricating a solar cell according to claim 9 , looking into the substrate and the pattern layer, when d is the thickness from the bottom surface of the grooves to the substrate in the pattern layer, and e is the thickness of the substrate, the conditional expression of (d)=Y(e) is satisfied, where Y has the value of from 0.04 to 0.12.

15. The method of fabricating a solar cell according to claim 9 , looking into the pattern layer, when f is the width of the grooves, and g is the width of the protrusions, the conditional expression of (f)=Z(g) is satisfied, where Z has the value of from 1 to 2.

Assignees

• Lee Dong Keun
• Lg Innotek Co Ltd

Inventors

• Lee Dong Keun

Classifications

• H10F19/33

  Patterning processes to connect the photovoltaic cells, e.g. laser cutting of conductive or active layers · CPC title

• H10F19/20

  comprising photovoltaic cells in arrays in or on a single semiconductor substrate, the photovoltaic cells having planar junctions (having multiple thin-film photovoltaic cells deposited on the same substrate H10F19/31) · CPC title

• H10F99/00

  Subject matter not provided for in other groups of this subclass · CPC title

• H10F77/1699

  the films including Group I-III-VI materials, e.g. CIS or CIGS on metal foils or polymer foils · CPC title

• H10F77/1696

  the films including Group II-VI materials, e.g. CdTe or CdS · CPC title