SOLUTION-BASED FABRICATION OF PHOTOVOLTAIC CELL

• US 20080142072A1
• Filed: 10/31/2007
• Published: 06/19/2008
• Est. Priority Date: 02/19/2004
• Status: Active Grant

• Current Assignee: Aeris Capital Sustainable IP, Ltd.
• Original Assignee: Brian M. Sager, Dong Yu, Jacqueline Fidanza
• Inventors: Yu, Dong, Sager, Brian M., Fidanza, Jacqueline
• Granted Patent: US 8,168,089 B2
• Time in Patent Office: Days
• US Class Current: 136/252
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: B82Y 5/00 Nanobiotechnology or nanomedicine, e.g. protein engineering or drug delivery
• CPC Class Codes: C23C 18/1204 inorganic material, e.g. non-oxide and non-metallic such as sulfides, nitrides based compounds
• CPC Class Codes: C23C 18/1266 Particles formed in situ
• CPC Class Codes: C23C 18/1295 with after-treatment of the deposited inorganic material
• 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 31/06 characterised by potential barriers
• 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

An ink for forming CIGS photovoltaic cell active layers is disclosed along with methods for making the ink, methods for making the active layers and a solar cell made with the active layer. The ink contains a mixture of nanoparticles of elements of groups IB, IIIA and (optionally) VIA. The particles are in a desired particle size range of between about 1 nm and about 500 nm in diameter, where a majority of the mass of the particles comprises particles ranging in size from no more than about 40% above or below an average particle size or, if the average particle size is less than about 5 nanometers, from no more than about 2 nanometers above or below the average particle size. The use of such ink avoids the need to expose the material to an H₂Se gas during the construction of a photovoltaic cell and allows more uniform melting during film annealing, more uniform intermixing of nanoparticles, and allows higher quality absorber films to be formed.

Claims

1. A method for fabricating a liquid containing intermixed elements of groups IB and IIIA, and optionally VIA, comprising the steps of:

forming non-oxide nanoparticles containing elements from group IB;

IIIA; and

VIA;

intermixing the non-oxide nanoparticles; and

mixing the non-oxide nanoparticles to form a liquid that serves as an ink,

wherein forming a mixture of non-oxide nanoparticles includes reacting a single-source precursor to form particles of IB-IIIA-VIA material.

2. The method of claim 1 wherein the single-source precursor is (PPh3)2CuIn(SEt)4.

3. The method of claim 1 wherein the single-source precursor is (PPh3)2CuIn(SePh)4.

4. The method of claim 1 wherein dioctyl phthalate is heated to at least about 125°

C. under vacuum to dry and degas the solvent.

5. The method of claim 4 wherein a container is back-filled with argon and cooled to room temperature prior to adding the precursor.

6. The method of claim 5 wherein (PPh₃)₂CuIn(SEt)₄ is then added to the reaction container and heating is resumed.

7. The method of claim 1 wherein at approximately 150°

C. the precursor is dissolved to form a transparent yellow solution, wherein at about 150°

C., the precursor remains, for the most part, intact.

8. The method of claim 1 wherein upon increase of the temperature to about 200°

C. or more a red powder begins to precipitate within a few minutes.

9. The method of claim 8 wherein a reaction time of about 2-3 hours is employed to complete the precipitation and maximize the yield.

10. The method of claim 9 wherein after cooling to room temperature under argon, toluene is added to the reaction mixture to lower a viscosity of the reaction mixture and the red powder may be isolated by centrifugation.

11. The method of claim 10 wherein the powder is consecutively washed with toluene and then an alcohol to remove any reaction byproducts and unreacted starting material, and then dried under vacuum at about 60 to about 80°

C.

12. The method of claim 11 wherein the washing and centrifugation steps are carried out in ambient atmosphere.

13. The method of claim 1 wherein the product is stored in an inert gas-filled container.

14. The method of claim 1 wherein a portion of the product is placed in a flask containing fresh dioctyl phthalate, heated to higher temperatures of about 250 to about 300°

C., and held at that temperature for about 1 hour or more.

15. The method of claim 1 wherein at a temperature of about 250°

C., a brown/black powder (CuInS₂) is obtained.

16. The method of claim 1 wherein at about 300°

C. the resulting powder is black and contains a CuInS₂ nanoparticulate.

17. The method of claim 1 wherein the precursor is dissolved in the dioctyl phthalate at 138°

C. or more.

18. The method of claim 2 wherein (PPh₃)₂CuIn(SePh)₄ is dissolved in dioctyl phthalate.

19. The method of claim 1 wherein a red powder is collected after heating at 200 to 300°

C. and this powder contains a CuInS (Se)₂ nanoparticulate.

20. The method of claim 1 wherein the non-oxide nanoparticles are added to a solvent to form a suspension.

21. The method of claim 1 wherein the non-oxide nanoparticles are added to a solvent to form a colloidal suspension.

22. The method of claim 1 wherein the size distributions of the CuInS₂ or CuIn(Se)₂ nanoparticulates is adjusted by size-selective precipitation, ultrafiltration and the like.

23. A photovoltaic device precursor material comprising:

a liquid ink comprising;

non-oxide metal nanoparticles containing elements from group IB, non-oxide metal nanoparticles from group IIIA; and

adding one or more liquid metals containing one or more elements of group IIIA, wherein forming a mixture of non-oxide quantum nanoparticles includes reacting a single-source precursor to form particles of IB-IIIA-VIA material;

a dispersant; and

a solvent.