Quaternary chalcogenide wafers

• US 8,480,944 B2
• Filed: 12/09/2010
• Issued: 07/09/2013
• Est. Priority Date: 12/09/2010
• Status: Expired due to Fees

• Current Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Ionkin, Alex Sergey, Fish, Brian M.
• Primary Examiner(s): Thrower, Larry
• Assistant Examiner(s): LIU, XUE H
• Application Number:
  US12/963,989
• Publication Number:
  US 20120146189A1
• Time in Patent Office: 943 Days
• Field of Search: 264/319
• US Class Current: 264/319
• CPC Class Codes: C01B 19/002 Compounds containing, besides selenium or tellurium, more than one other element, with -O- and -OH not being considered as anions
• CPC Class Codes: C01B 19/007 Tellurides or selenides of metals C01B19/002 takes precedence
• CPC Class Codes: C01G 19/006 Compounds containing, besides tin, two or more other elements, with the exception of oxygen or hydrogen
• CPC Class Codes: C01P 2004/51 Particles with a specific particle size distribution
• CPC Class Codes: C01P 2004/61 Micrometer sized, i.e. from 1-100 micrometer
• CPC Class Codes: C01P 2004/62 Submicrometer sized, i.e. from 0.1-1 micrometer
• CPC Class Codes: C04B 2235/3201 Alkali metal oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3281 Copper oxides, cuprates or oxide-forming salts thereof, e.g. CuO or Cu2O
• CPC Class Codes: C04B 2235/3284 Zinc oxides, zincates, cadmium oxides, cadmiates, mercury oxides, mercurates or oxide forming salts thereof
• CPC Class Codes: C04B 2235/3293 Tin oxides, stannates or oxide forming salts thereof, e.g. indium tin oxide [ITO]
• CPC Class Codes: C04B 2235/444 Halide containing anions, e.g. bromide, iodate, chlorite
• CPC Class Codes: C04B 2235/446 Sulfides, tellurides or selenides
• CPC Class Codes: C04B 2235/5436 micrometer sized, i.e. from 1 to 100 micron
• CPC Class Codes: C04B 2235/5445 submicron sized, i.e. from 0,1 to 1 micron
• CPC Class Codes: C04B 2235/604 Pressing at temperatures other than sintering temperatures
• CPC Class Codes: C04B 2235/72 Products characterised by the absence or the low content of specific components, e.g. alkali metal free alumina ceramics
• CPC Class Codes: C04B 2235/94 Products characterised by their shape
• CPC Class Codes: C04B 2235/95 Products characterised by their size, e.g. microceramics
• CPC Class Codes: C04B 35/547 based on sulfides or selenides or tellurides
• CPC Class Codes: C04B 35/6261 Milling
• CPC Class Codes: C04B 35/62655 : Drying, e.g. freeze-drying, spray-drying, microwave or supercritical drying
• CPC Class Codes: C04B 35/636 : Polysaccharides or derivatives thereof

Abstract

Disclosed herein are processes for making quaternary chalcogenide wafers. The process comprises milling quaternary chalcogenide crystals to form milled particles, and then compressing the milled particles to form a quaternary chalcogenide wafer. The quaternary chalcogenide wafers are useful for forming solar cells.

Claims

1. A non-vacuum based process for making a quaternary chalcogenide wafer comprising:

a. milling quaternary chalcogenide crystals to form milled particles with a particle size, d90 in the range of 0.1 micron to 10 microns, wherein the quaternary chalcogenide crystals are selected from the group consisting of Cu₂ZnSnS₄ (CZTS);

Cu₂ZnSn(Sa,Se_1-a)₄, where 0≦

a≦

1 (CZTS/Se); and

Cu₂ZnSnSe₄ (CZTSe);

b. compressing the milled particles at a temperature in the range of room temperature to 250°

C. to form a quaternary chalcogenide wafer having a thickness in the range of 10 microns to 300 microns.

2. The process of claim 1, wherein the particle size, d₉₀ of the milled particles is in the range of about 0.8 microns to about 2.5 microns.

3. The process of claim 1, wherein the step of compressing the milled particles comprises compressing the milled particles at a pressure in the range of 15 MPa to 463 MPa.

4. The process of claim 1, wherein the step of compressing the milled particles comprises compressing the milled particles under nitrogen.

5. The process of claim 1, further comprising mixing the milled particles with a binder before the step of compressing the milled particles.

6. The process of claim 5, wherein the binder comprises sulfur, corn starch, cesium chloride, or mixtures thereof.

7. The process of claim 1, further comprising sintering the quaternary chalcogenide wafer at a temperature in the range of about 100°

C. to about 950°

C. for a period of about 5 minutes to 2.5 hours.