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 graphene nanomaterials having a controlled number of atomic layer(s).
1. A method for separating planar nanomaterials by thickness, the method comprising:
centrifuging a nanomaterial composition in contact with an aqueous fluid medium comprising a density gradient, wherein the nanomaterial composition comprises one or more surface active components and a polydisperse population of planar materials which is polydisperse at least with respect to thickness and has a mean thickness on the order of nanometers; and
separating the nanomaterial composition into two or more separation fractions each comprising a subpopulation of planar nanomaterials from the polydisperse population, wherein the subpopulation of planar 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 planar nanomaterials have not be subjected to covalent modification.
3. The method of claim 2 , wherein the planar nanomaterials have not been oxidized.
4. The method of claim 1 , wherein the planar nanomaterials comprise graphene.
5. The method of claim 1 , wherein the planar nanomaterials comprise molybdenum sulfide or boron nitride.
6. The method of claim 1 , wherein the one or more surface active components comprise a planar organic group.