Solar cell having three-dimensional p-n junction structure and method for manufacturing same

Patent metadata

Field	Value
Publication number	US-2016240709-A1
Application number	US-201415025677-A
Country	US
Kind code	A1
Filing date	Sep 24, 2014
Priority date	Sep 30, 2013
Publication date	Aug 18, 2016
Grant date	—

Abstract

The present invention provides a 3-dimensional P-N junction solar cell composed of a base board coated with a back plate on the upper face of the same; a P type semiconductor thin film formed on the top side of the back plate which has a 3-dimensional porous structure and is composed of P type semiconductor crystal grains; a N type buffer layer formed on the surface of the crystal grains of the said P type semiconductor thin film with playing a role of coating the thin film; and a transparent electrode formed on the surface of the crystal grains of the P type semiconductor thin film on which the N type buffer layer is formed. The solar cell of the present invention is a P-N junction solar cell including a 3-dimensional photo catalytic thin film, which can provide an improved photoelectric conversion efficiency, compared with the conventional P-N junction solar cell, owing to the formation of the N-type buffer layer on the surface of the crystal grains of the 3-dimensional P type semiconductor thin film.

First claim

What is claimed is:

1 . A 3-dimensional P-N junction solar cell comprising:
a base board coated with a back plate on the upper face of the same; a P type semiconductor thin film formed on the top side of the back plate which has a 3-dimensional porous structure and is composed of P type semiconductor crystal grains; a N type buffer layer formed on the surface of the crystal grains of the said P type semiconductor thin film with playing a role of coating the thin film; and a transparent electrode formed on the surface of the crystal grains of the P type semiconductor thin film on which the N type buffer layer is formed.

2 . The 3-dimensional P-N junction solar cell according to claim 1 , wherein the N type buffer layer contains one of those compounds selected from the group consisting of CdS, TiO 2 , ZnO 2 , Zn(O,S), ZnMgO, and CdSe.

3 . The 3-dimensional P-N junction solar cell according to claim 1 , wherein the N type buffer layer contains a conducting polymer selected from the group consisting of [6,6]-phenyl-C85 butyric acid methyl ester (PCBM), polyaniline (PANI), polyacetylene, and polythiophene.

4 . The 3-dimensional P-N junction solar cell according to claim 1 , wherein the thickness of the N type buffer layer is 20˜150 nm

5 . The 3-dimensional P-N junction solar cell according to claim 1 , wherein the 3-dimensional porous P type semiconductor thin film is composed of a compound selected from the group consisting of CuInS 2 (CIS), CuGaS 2 (CGS), CuInSe 2 (CISe), CuGaSe 2 (CGSe), CuAlSe 2 (CASe), CuInTe2 (CITe), CuGaTe2 (CCTe), Cu(In,Ga)S2 (CIGS), Cu(In,Ga)Se2 (CIGSe), Cu 2 ZnSnS 4 (CZTS), Cu 2 ZnSnSe 4 (CZTSe), Cu 2 ZnSn(S,Se) 4 (CZTSSe), CuSbS 2 , AgSbS 2 , and CdTe.

6 . The 3-dimensional P-N junction solar cell according to claim 1 , wherein the size of the crystal grains forming the porous P type semiconductor thin film is 30˜200 nm.

7 . The 3-dimensional P-N junction solar cell according to claim 1 , wherein the P type semiconductor thin film is formed with 20˜80% of porosity.

8 . The 3-dimensional P-N junction solar cell according to claim 1 , wherein the surface roughness of the P type semiconductor thin film is 50˜100 nm.

9 . The 3-dimensional P-N junction solar cell according to claim 1 , wherein the solar cell additionally contains a blocking layer between the back plate and the P type semiconductor thin film.

10 . The 3-dimensional P-N junction solar cell according to claim 9 , wherein the blocking layer contains a compound selected from the group consisting of MoO x , NiO 2 , Cu 2 O, SnO x , TiO 2 , ZnO, and Al 2 O 3 .

11 . The 3-dimensional P-N junction solar cell according to claim 9 , wherein the thickness of the blocking layer is 5˜20 nm.

12 . The 3-dimensional P-N junction solar cell according to claim 1 , wherein the transparent electrode formed on the top surface of the 3-dimensional porous P type semiconductor thin film laminated with the N type buffer layer contains a compound selected from the group consisting of ZnO, indium tin oxide (ITO), and SnO 2 .

13 . The 3-dimensional P-N junction solar cell according to claim 1 , wherein at least a part of the N type buffer layer is supposed to contact the transparent electrode.

14 . A preparation method of a 3-dimensional P-N junction solar cell comprising the following steps:
forming a 3-dimensional porous P type semiconductor thin film on top of the base board coated with the back plate (step 1); coating the surface of the crystal grains of the P type semiconductor thin film with the N type buffer layer (step 2); and forming a transparent electrode on the P type semiconductor thin film on which the N type buffer layer is formed in step 2 (step 3).

15 . The preparation method of a 3-dimensional P-N junction solar cell according to claim 14 , wherein the P type semiconductor thin film of step 1 contains a compound selected from the group consisting of CuInS 2 (CIS), CuGaS 2 (CGS), CuInSe 2 (CISe), CuGaSe 2 (CGSe), CuAlSe 2 (CASe), CuInTe2 (CITe), CuGaTe2 (CCTe), Cu(In,Ga)S2 (CIGS), Cu(In,Ga)Se2 (CIGSe), Cu 2 ZnSnS 4 (CZTS), Cu 2 ZnSnSe 4 (CZTSe), Cu 2 ZnSn(S,Se) 4 (CZTSSe), CuSbS 2 , AgSbS 2 , and CdTe.

16 . The preparation method of a 3-dimensional P-N junction solar cell according to claim 14 , wherein the P type semiconductor thin film of step 1 is made of Cu 2 ZnSnS 4 (CZTS).

17 . The preparation method of a 3-dimensional P-N junction solar cell according to claim 14 , wherein the CZTS P type semiconductor thin film is prepared by the following steps:
preparing a CZTS precursor solution by mixing a raw material comprising a copper precursor, a zinc precursor, a tin precursor, and a sulfur or selenium precursor with a solvent (step A); coating the base board with the prepared precursor solution (step B); pre-heating the coated thin film at 200˜400° C. (step C); and heating the pre-heated thin film at 500˜600° C. in the presence of one or more gases selected from the group consisting of sulfur and selenium (step D).

18 . The preparation method of a 3-dimensional P-N junction solar cell according to claim 14 , wherein the coating of step 2 is performed by one of the methods selected from the group consisting of chemical bath deposition (CBD), atomic layer deposition (ALD), successive ionic layer adsorption and reaction (SILAR), sputter, and spray coating.

19 . The preparation method of a 3-dimensional P-N junction solar cell according to claim 14 , wherein the transparent electrode of step 2 contains a compound selected from the group consisting of ZnO, indium tin oxide (ITO), and SnO 2 .

20 . A preparation method of a porous CZTS thin film comprising the following steps:
preparing a CZTS precursor solution by mixing one or more precursors selected from the group consisting of a copper precursor, a zinc precursor, a tin precursor, and a sulfur or selenium precursor with a solvent (step 1); coating the base board with the prepared precursor solution (step 2); pre-heating the coated thin film at 200˜400° C. (step 3); and heating the pre-heated thin film at 500˜600° C. in the presence of one or more gases selected from the group consisting of sulfur and selenium (step 4).

21 . The preparation method of a porous CZTS thin film according to claim 20 , wherein the copper precursor of step 1 is one or more chloride materials selected from the group consisting of CuCl, CuCl 2 , and CuCl 2 .H 2 O.

22 . The preparation method of a porous CZTS thin film according to claim 20 , wherein the zinc precursor of step 1 is ZnCl 2 .

23 . The preparation method of a porous CZTS thin film according to claim 20 , wherein the tin precursor of step 1 is one or more chloride materials selected from the group consisting of SnCl 2 , SnCl 2 .H 2 O and SnCl 4 .

24 . The preparation method of a porous CZTS thin film according to claim 20 , wherein the sulfur precursor of step 1 is one or more compounds selected from the group consisting of CH 4 N 2 S, S(NH 4 ) 2 , (NH 4 ) 2 SO 4 , (CH 3 ) 2 S(C 2 H 5 ) 2 S, (CH 3 ) 3 SH, (CH 3 ) 2 CHCH 2 SH, CH 3 (CH 2 ) 3 SH, CH 3 CH 2 CH(SH)CH 3 , and CH 3 CSNH 2 .

25 . The preparation method of a porous CZTS thin film according to claim 20 , wherein the selenium precursor of step 1 is one or more compounds selected from the group consisting of SeC(NH 2 ) 2 , (CH 3 ) 2 NC(Se)NH 2 , SeCl 4 , (CH 3 ) 2 Se, Se(C 2 H 5 ) 2 , Na 2 SeO 3 , and H 2 SeO 3 .

Assignees

• Daegu Gyeongbuk Inst Science & Tech

Inventors

• Sung Shi-Joon
• Park Si-Nae
• Kim Dae-Hwan
• Kang Jin-Kyu
• Hwang Dae-Kue

Classifications

• H10F77/128

  comprising only Group I-II-IV-VI kesterite materials, e.g. Cu2ZnSnSe4 or Cu2ZnSnS4 · CPC title

• H10F77/14

  Shape of semiconductor bodies; Shapes, relative sizes or dispositions of semiconductor regions within semiconductor bodies · CPC title

• H10F19/30

  comprising thin-film photovoltaic cells · CPC title

• H10F10/167

  comprising Group I-III-VI materials, e.g. CdS/CuInSe2 [CIS] heterojunction photovoltaic cells · CPC title

• H10F10/16

  Photovoltaic cells having only PN heterojunction potential barriers · CPC title