Method to synthesize colloidal iron pyrite (FeS2) nanocrystals and fabricate iron pyrite thin film solar cells

Patent metadata

Field	Value
Publication number	US-9862617-B2
Application number	US-201514749212-A
Country	US
Kind code	B2
Filing date	Jun 24, 2015
Priority date	Apr 2, 2010
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

Systems and methods are provided for the fabrication and manufacture of efficient, low-cost p-n heterojunction pyrite solar cells. The p-n heterojunction pyrite solar cells can include a pyrite thin cell component, a window layer component, and a top surface contact component. The pyrite thin cell component can be fabricated from nanocrystal paint deposited onto metal foils or microcrystalline pyrite deposited onto foil by chemical vapor deposition. A method of synthesizing colloidal pyrite nanocrystals is provided. Methods of manufacturing the efficient, low-cost p-n heterojunction pyrite solar cells are also provided.

First claim

What is claimed is:

1. A method for producing pyrite thin films, comprising the steps of
synthesizing colloidal pyrite nanocrystals,
purifying the colloidal pyrite nanocrystals,
depositing a p-type pyrite thin film comprising the colloidal pyrite nanocrystals onto a conductive bottom substrate, the conductive bottom substrate acting as an electrical contact; and
sintering the p-type pyrite thin film in sulfur-containing atmospheres, wherein the step of synthesizing colloidal pyrite nanocrystals comprises the steps of
creating a reaction solution by mixing FeCl2 with octadecylamine;
degassing the reaction solution;
creating an injection solution by injecting and dissolving sulfur in a solvent;
degassing the injection solution;
raising the temperature of the reaction solution;
adding the injection solution to the reaction solution to create a reaction mixture; and
heating the reaction solution for a period of time.

2. The method of claim 1 wherein the step of depositing the p-type pyrite thin film includes dipping, spinning, dropping, printing, or spraying onto the conductive bottom substrate.

3. The method of claim 1 wherein the sulfur-containing atmospheres comprise S2, H2S, or tert-butyl disulfide.

4. The method of claim 1 wherein the solvent comprises one of diphenyl ether, tri-n-octylphosphine oxide, octadecene, nonpolar organic solvent, or water.

5. The method of claim 1 wherein the step of raising the temperature of the reaction solution includes raising the temperature to 220° C.

6. The method of claim 1 wherein the period of time is 2 hours.

7. The method of claim 1 wherein the step of depositing a thin film of p-type pyrite includes depositing pyrite onto the conductive bottom substrate by chemical vapor deposition.

8. The method of claim 7 wherein the p-type pyrite is microcrystalline pyrite.

9. A method for producing pyrite thin films, comprising the steps of
synthesizing colloidal pyrite nanocrystals,
purifying the colloidal pyrite nanocrystals,
depositing a p-type pyrite thin film comprising the colloidal pyrite nanocrystals onto a conductive bottom substrate, the conductive bottom substrate acting as an electrical contact; and
sintering the p-type pyrite thin film in sulfur-containing atmospheres, wherein synthesizing the colloidal pyrite nanocrystals comprises the steps of:
heating FeCl 2 and elemental sulfur in octadecylamine and diphenyl ether; and
forming colloidal pyrite nanocrystals from the heated FeCl 2 and elemental sulfur in octadecylamine and diphenyl ether.

10. The method of claim 9 wherein the conductive bottom substrate is flexible.

11. The method of claim 10 wherein the conductive bottom substrate comprises one of a metal foil, glass, quartz, or silicon that serves as a bottom contact in a pyrite thin film solar cell.

12. The method of claim 9 further comprising stabilizing the p-type pyrite thin film nanocrystal with ligands.

13. The method of claim 12 wherein the ligands comprise one of long-chain octadecylxanthates, alkylammonium, or alkylxanthates.

14. The method of claim 9 wherein the step of purifying the colloidal pyrite nanocrystals consists of washing the colloidal pyrite nanocrystals with a chloroform and ethanol mixture.

15. The method of claim 9 wherein the step of depositing the colloidal pyrite nanocrystals onto a substrate comprises the steps of dipping the substrate a plurality of times into a solution of colloidal pyrite nanocrystals.

16. The method of claim 15 wherein the solution of colloidal pyrite nanocrystals includes a mixture of colloidal pyrite nanocrystals and hydrazine.

17. The method of claim 9 wherein the step of heating includes heating the FeCl 2 and elemental sulfur in octadecylamine and diphenyl ether to 220° C. for a plurality of hours.

18. The method of claim 9 wherein the step of depositing the p-type pyrite thin film includes dipping, spinning, dropping, printing, or spraying onto the conductive bottom substrate.

19. The method of claim 9 wherein the sulfur-containing atmospheres comprise S2, H2S, or tert-butyl disulfide.

Assignees

• Univ California

Inventors

• Law Matthew
• Seefeld Sean
• Puthussery James

Classifications

• C01P2004/03

  obtained by SEM · CPC title

• B82Y30/00

  Nanotechnology for materials or surface science, e.g. nanocomposites · CPC title

• Y02E10/50

  Photovoltaic [PV] energy · CPC title

• C01P2002/72

  by d-values or two theta-values, e.g. as X-ray diagram · CPC title

• C23C16/56

  After-treatment · CPC title