Photovoltaic Device with Solution-processed Chalcogenide Absorber Layer

• US 20090145482A1
• Filed: 12/06/2007
• Published: 06/11/2009
• Est. Priority Date: 12/06/2007
• Status: Active Grant

• Current Assignee: Globalfoundries US Incorporated (GlobalFoundries, Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Yuan, Min, Liu, Wei, Mitzi, David B.
• Granted Patent: US 8,613,973 B2
• Time in Patent Office: Days
• US Class Current: 136/262
• CPC Class Codes: H01L 31/0322 comprising only AIBIIICVI chalcopyrite compounds, e.g. Cu In Se2, Cu Ga Se2, Cu In Ga Se2
• CPC Class Codes: H01L 31/0324 comprising only AIVBVI or AIIBIVCVI chalcogenide compounds, e.g. Pb Sn Te
• CPC Class Codes: H01L 31/0749 including a AIBIIICVI compound, e.g. CdS/CulnSe2 [CIS] heterojunction solar cells
• CPC Class Codes: H01L 31/18 Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
• CPC Class Codes: Y02E 10/541 CuInSe2 material PV cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

The present invention provides a photovoltaic device, such as, a solar cell, having a substrate and an absorber layer disposed on the substrate. The absorber layer includes a doped or undoped composition represented by the formula: Cu_1-yIn_1-xGa_xSe_2-zS_z wherein 0≦x≦1; 0≦y≦0.15 and 0≦z≦2; wherein the absorber layer is formed by a solution-based deposition process which includes the steps of contacting hydrazine and a source of Cu, a source of In, a source of Ga, a source of Se, and optionally a source of S, and further optionally a source of a dopant, under conditions sufficient to produce a homogeneous solution; coating the solution on the substrate to produce a coated substrate; and heating the coated substrate to produce the photovoltaic device. A photovoltaic device and a process for making same based on a hydrazinium-based chalcogenide precursor are also provided.

Claims

1. A photovoltaic device comprising:

a substrate; and

an absorber layer disposed on said substrate;

wherein said absorber layer comprises a doped or undoped composition represented by the formula;

Cu_1-yIn_1-xGa_xSe_2-zS_z

wherein 0≦

x≦

1;

≦

y≦

0.15; and

0≦

z≦

2,

wherein said absorber layer is formed by a solution-based deposition process comprising the steps of;

contacting hydrazine and a source of Cu, a source of In, a source of Ga, a source of Se, and optionally a source of S, and further optionally a source of a dopant, under conditions sufficient to produce a homogeneous solution;

coating said solution on said substrate to produce a coated substrate; and

heating said coated substrate to produce said photovoltaic device.

2. The photovoltaic device of claim 1, wherein said source of Cu, said source of In, said source of Ga, said source of Se, and said source of S, if present, are in amounts sufficient to produce an absorber layer having a predetermined composition.

3. The photovoltaic device of claim 2, wherein said solution-based deposition process employs a soluble molecular precursor in a solution which is substantially free of C, O, Cl, Br, and I impurities.

4. The photovoltaic device of claim 2, wherein said absorber layer has a composition represented by the formula represented by CuInSe₂.

5. The photovoltaic device of claim 2, wherein said absorber layer has a composition represented by the formula represented by CuIn_0.85Ga_0.15Se₂.

6. The photovoltaic device of claim 2, wherein said absorber layer has a composition represented by the formula CuIn_0.7Ga_0.3Se₂.

7. The photovoltaic device of claim 2, wherein said absorber layer has a composition represented by the formula 0.75 mol % Sb doped CuInSe₂.

8. The photovoltaic device of claim 1, wherein said absorber layer has a composition represented by the formula 1.0 mol % Sb doped CuInSe₂.

9. The photovoltaic device of claim 1, wherein said substrate is selected from the group consisting of:

glass, Mo-coated glass, Si/SiO₂, metal foil, molybdenum foil, polyimide (Kapton) sheet, and Mo-coated polyimide.

10. The photovoltaic device of claim 1, wherein said coating step in said solution-based process is selected from the group consisting of:

spin-coating, stamping, printing, doctor blading, spraying, and dipping.

11. The photovoltaic device of claim 1, wherein said heating step is carried out at a temperature from about 50°

C. to about 600°

C., and for a period of time from about 5 sec to about 10 hr.

12. The photovoltaic device of claim 11, wherein said temperature is from about 350°

C. to about 550°

C., and said period of time is from about 5 min to about 45 min.

13. The photovoltaic device of claim 1, wherein the steps of coating and heating are repeated at least once to deposit multiple layers of the same or different compositions to produce a stack having the same or different layers.

14. The photovoltaic device of claim 13, wherein the steps of coating and heating are repeated to produce a film having a uniform or a graded composition.

15. The photovoltaic device of claim 1, wherein the absorber layer has a large grain structure to minimize recombination at the grain boundaries.

16. The photovoltaic device of claim 15, wherein the grain size is from about 0.2 μ

m to about 2.0 μ

m.

17. The photovoltaic device of claim 1, wherein the absorber layer has a thickness of at least about 200 nm.

18. A photovoltaic device comprising:

a substrate; and

an absorber layer disposed on said substrate;

wherein said absorber layer comprises a doped or undoped composition represented by the formula;

Cu_1-yIn_1-xGa_xSe_2-zS_z

wherein 0≦

x≦

1;

0≦

y≦

0.15; and

0≦

z≦

2

wherein said absorber layer is formed by a solution-based deposition process comprising the steps of;

contacting a hydrazinium-based chalcogenide precursor and a solvent, under conditions sufficient to produce a homogeneous solution;

coating said solution on said substrate to produce a coated substrate; and

heating said coated substrate to produce said photovoltaic device.

19. The photovoltaic device of claim 18, wherein said solvent is a non-hydrazine solvent.

20. The photovoltaic device of claim 19, wherein said non-hydrazine solvent is selected from the group consisting of:

ethanolamine, DMSO, and a mixture thereof.

21. The photovoltaic device of claim 18, wherein said solution-based deposition process employs a hydrazinium-based chalcogenide precursor in a solution which is free of Cl, Br, and I impurities.

22. A solution-based deposition process for depositing an absorber layer on a substrate wherein said absorber layer comprises a doped or undoped composition represented by the formula:

wherein 0≦

x≦

1; and

0≦

y≦

0.15; and

0≦

z≦

2

said process comprising the steps of;

contacting hydrazine and a source of Cu, a source of In, a source of Ga, a source of Se, and optionally a source of S, and further optionally a source of a dopant, under conditions sufficient to produce a homogeneous solution;

coating said solution on said substrate to produce a coated substrate; and

heating said coated substrate to produce said absorber layer.

23. The process of claim 22, wherein said source of Cu, said source of In, said source of Ga, said source of Se, and said source of S, if present, are in amounts sufficient to produce an absorber layer having a predetermined composition.

24. The process of claim 22, wherein said solution-based deposition process employs a soluble molecular precursor in a solution which is free of C, O, Cl, Br, and I impurities.

25. A solution-based deposition process for depositing an absorber layer on a substrate wherein said absorber layer comprises a doped or undoped composition represented by the formula:

Cu_1-yIn_1-xGa_xSe_2-zS_z

wherein 0≦

x≦

1;

0≦

y≦

0.15; and

0≦

z≦

2

said process comprising the steps of;

contacting a hydrazinium-based chalcogenide precursor and a solvent, under conditions sufficient to produce a homogeneous solution;

coating said solution on said substrate to produce a coated substrate; and

heating said coated substrate to produce said absorber layer.

26. The process of claim 25, wherein said solution-based deposition process employs a hydrazinium-based chalcogenide precursor in a solution which is free of Cl, Br, and I impurities.

27. The process of claim 25, wherein said solvent is a non-hydrazine solvent.

28. The process of claim 27, wherein said non-hydrazine solvent is selected from the group consisting of:

ethanolamine, DMSO, and a mixture thereof.