Sorting two-dimensional nanomaterials by thickness
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).
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.