Sorting two-dimensional nanomaterials by thickness

Patent metadata

Field	Value
Publication number	US-9890043-B2
Application number	US-201514869547-A
Country	US
Kind code	B2
Filing date	Sep 29, 2015
Priority date	Aug 14, 2009
Publication date	Feb 13, 2018
Grant date	Feb 13, 2018

Abstract

The present teachings provide, in part, methods of separating two-dimensional nanomaterials by atomic layer thickness. In certain embodiments, the present teachings provide methods of generating boron nitride nanomaterials having a controlled number of atomic layer(s).

First claim

We claim:

1. A method for separating planar nanomaterials by thickness, the method comprising:
centrifuging a boron nitride nanomaterial composition in contact with an aqueous fluid medium comprising a density gradient, wherein the boron nitride nanomaterial composition comprises one or more surface active components and a polydisperse population of planar boron nitride nanomaterials comprising monolayer, bilayer and tri-layer boron nitride nanomaterials, which is polydisperse at least with respect to thickness and has a mean thickness on the order of nanometers; and
separating the boron nitride nanomaterial composition into two or more separation fractions each comprising a subpopulation of planar boron nitride nanomaterials from the polydisperse population, wherein the subpopulation of planar boron nitride nanomaterials in at least one of the two or more separation fractions has a mean thickness that is less than the mean thickness of the polydisperse population.

2. The method of claim 1 , wherein the planar nanomaterials comprise planar hexagonal boron nitride nanomaterials.

3. The method of claim 1 , wherein the one or more surface active components comprise a planar organic group.

4. The method of claim 3 , wherein the one or more surface active components is a copolymer of oxyethylene and oxypropylene.

5. A method for separating hexagonal boron nitride nanomaterials by thickness, the method comprising:
sonicating hexagonal boron nitride in a first fluid medium to provide a hexagonal boron nitride nanomaterial composition;
centrifuging the hexagonal boron nitride nanomaterial composition in contact with an aqueous second fluid medium comprising a density gradient, wherein the hexagonal boron nitride nanomaterial composition comprises one or more surface active components and a polydisperse population of planar hexagonal boron nitride nanomaterials comprising monolayer, bilayer, trilayer and n-layer hexagonal boron nitride nanomaterials, where n is an integer in the range of 4 to 10; and
separating the hexagonal boron nitride nanomaterial composition into two or more separation fractions each comprising a subpopulation of planar hexagonal boron nitride nanomaterials from the polydisperse population, wherein the subpopulation in at least one of the two or more separation fractions comprises greater than 50% of the monolayer hexagonal boron nitride nanomaterials, bilayer hexagonal boron nitride nanomaterials, trilayer hexagonal boron nitride nanomaterials, or combinations thereof.

6. The method of claim 5 , wherein the subpopulation in at least one of the two or more separation fractions comprises greater than 30% of the monolayer or bilayer hexagonal boron nitride nanomaterials, or a combination thereof.

7. The method of claim 5 , wherein the one or more surface active components comprise an amphiphilic compound having a planar core.

8. The method of claim 7 , wherein the one or more surface active components is a copolymer of oxyethylene and oxypropylene.

9. The method of claim 5 , wherein the subpopulation in one of the separation fractions comprises greater than 80% of the monolayer hexagonal boron nitride.

10. The method of claim 5 , wherein a subpopulation of at least one of the two or more separation fractions is deposited on a substrate.

11. The method of claim 10 , wherein the subpopulation in one of the separation fractions comprises greater than 80% of the monolayer hexagonal boron nitride and is deposited on the substrate.

12. The method of claim 11 , wherein the substrate and hexagonal boron nitride deposited thereon are incorporated into an electronic heterostructure device.

13. A method for separating monolayer hexagonal boron nitride nanomaterials, the method comprising:
centrifuging a hexagonal boron nitride nanomaterial composition in contact with an aqueous fluid medium comprising a density gradient, wherein the hexagonal boron nitride nanomaterial composition comprises one or more copolymers of oxyethylene and oxypropylene and a polydisperse population of planar hexagonal boron nitride nanomaterials comprising monolayer, bilayer and trilayer hexagonal boron nitride nanomaterials; and
separating the hexagonal boron nitride nanomaterial composition into two or more separation fractions each comprising a subpopulation of planar hexagonal boron nitride nanomaterials from the polydisperse population, wherein the subpopulation in one of the two or more separation fractions comprises greater than 50% of the monolayer hexagonal boron nitride nanomaterials.

14. The method of claim 13 , wherein the subpopulation in the one of the two or more separation fractions comprises greater than 80% of the monolayer hexagonal boron nitride nanomaterial.

15. The method of claim 13 , wherein a subpopulation of at least one of the two or more separation fractions is deposited on a substrate.

16. The method of claim 15 , wherein the subpopulation in one of the separation fractions comprises greater than 80% of the monolayer hexagonal boron nitride and is deposited on the substrate.

17. The method of claim 16 , wherein the substrate and hexagonal boron nitride deposited thereon are incorporated into an electronic heterostructure device.

Assignees

• Univ Northwestern

Inventors

• Hersam Mark C
• Green Alexander A
• Zhu Jian

Classifications

• C01G39/06

  Sulfides · CPC title

• C04B2235/5454

  nanometer sized, i.e. below 100 nm · CPC title

• C01G29/006

  Compounds containing bismuth, with or without oxygen or hydrogen, and containing two or more other elements · CPC title

• B01D21/26

  Separation of sediment aided by centrifugal force {or centripetal force}(centrifuges B04B; cyclones B04C) · CPC title

• C01B2204/28

  Solid content in solvents · CPC title