Photovoltaic device with solution-processed chalcogenide absorber layer

• US 8,613,973 B2
• Filed: 12/06/2007
• Issued: 12/24/2013
• Est. Priority Date: 12/06/2007
• Status: Active Grant

• Current Assignee: Globalfoundries US Incorporated (GlobalFoundries, Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Mitzi, David B., Liu, Wei, Yuan, Min
• Primary Examiner(s): VETERE, ROBERT A
• Application Number:
  US11/951,858
• Publication Number:
  US 20090145482A1
• Time in Patent Office: 2,210 Days
• Field of Search: 427/226
• US Class Current: 427/74
• 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 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.

2. The process of claim 1, wherein said solution-based deposition process employs a hydrazinium-based chalcogenide precursor in a solution which is free of Cl, Br, and I impurities.

3. The process of claim 1, wherein said solvent is a non-hydrazine solvent.

4. The process of claim 3, wherein said non-hydrazine solvent is selected from the group consisting of:

ethanolamine, DMSO, and a mixture thereof.

5. The process of claim 1, wherein said absorber layer has a composition represented by the formula represented by CuInSe₂.

6. The process of claim 1, wherein said absorber layer has a composition represented by the formula represented by CuIn_0.85Ga_0.15Se₂.

7. The process of claim 1, wherein said absorber layer has a composition represented by the formula CuIn_0.7Ga_0.3Se₂.

8. The process of claim 1, wherein said absorber layer has a composition represented by the formula 0.75 mol % Sb doped CuInSe₂.

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

10. The process 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.

11. The process 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.

12. The process 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.

13. The process of claim 12, 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.

14. The process 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.

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

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

17. The process of claim 16, wherein the grain size is from about 0.2 μ

m to about 2.0 μ

m.

18. The process of claim 1, wherein the absorber layer has a thickness of at least about 200 nm.