In this presentation, I have tried to define Nanostructures and discuss various types of Nanostructures. I have also compared the ways in which Nanomaterials can be synthesized.

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Peeyush Mishra | NIT CALICUT
CLASSIFICATION OF NANOSTRUCTURES
 Nanomaterials: ISO (International Organization for
Standardization) defines nanomaterials as ‘material with any
external dimension in the nanoscale (size range from
approximately 1 – 100 nm) or having an internal structure or
surface structure in the nanoscale’.
 Richard W. Seigel, the professor and director of Material
Science and Engineering at Rensselaer Polytechnic Institute
and fellow of the Material Science Society (MRS) classified
nanostructured materials in the following way:
1. Zero dimensional: These are the materials having all
the dimensions within the nanoscale (no dimensions are
larger than 100 nm). Small clusters composed of a few to
roughly a hundred metal atoms, and common spherical
metal nanoparticles.
Example: - Quantum dots, Nanodots, Nanoclusters and
Fullerenes.
2. One dimensional: These are the materials having one
dimension outside the nanoscale (one dimension is larger
than 100 nm). Major growth occurs in one dimension,
whereas it is limited in the other two dimensions
Example: - Nanowires, Nanorods, Nanotubes, Nanowires,
Nanobelts, Nanopillars, Carbon Nanotubes (CNT).

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3. Two dimensional: These are the materials having two
dimensions outside the nanoscale. (Two dimensions are
larger than 100nm). This class exhibits plate-like shapes.
Example: - Graphene, nanofilms, nanoplates,
nanonetwork, planar triangle, hexagons and discs.
4. Three dimensional: These are the materials that are
not confined to the nanoscale in any dimensions. (All
three dimensions are larger than 100nm). Major growth
occurs in all three dimensions, more complicated
structures like various polyhedral, as well as assemblies
of 0D, 1D and 2D nanostructures
Example: -Graphite, Diamond, Nanosponge,
Nanocomposite, dispersion of nanoparticles, a bundle of
nanowires.
Nanomaterials
Zero Dimensional
One Dimensional
Two Dimensional
Three Dimensional

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 Identifying the nanostructures
(a) 0D Spheres and clusters
(b)1D Nanofibers, wires and rods
(c)2D films, plates and networks
(d)3D Nanomaterials
 TEM images of various dimensional ZnO nanostructures
1. 0D ZnO nanospheres

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2. 1D ZnO Nanowires
3. 2D ZnO Nanosheets
4. 3D ZnO nanostructure
(It’s aggregates of 1D Zinc Nanotubes)

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 Basic Synthetic Approach
Top-down Approach Bottom-up Approach
Breaking of large objects Assembling atoms and molecules
Structure sizes in the medium
to lower nm range starting
from large materials entity
Designing Nanoparticles of any
size and morphology by unit-by-
unit deposition of the constituents.

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 Keywords:
Quantum dots: 0D structures having all the dimensions less than
10nm
Nanodots: 0D structures having all dimensions less than 100nm;
perfectly spherical in shape.
Nanoclusters:0D structures having all dimensions less than
100nm; they are asymmetrical in shape.
Fullerenes: 0D carbon structure made up of single and double
bonds forming a closed mesh shape; made from fused rings of 5-
7 atoms.
Initial
Stage
Final
Stage
Initial
Stage

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Nanotube:1D structures which are hollow from inside
Nanorod: 1D structures which are solids and are not hollow from
within.
Nanowires: 1D structures which are known for their electrical
conducting property.
Nanopillars and Nanobelts: 1D structures named on basis of their
shape. (refer identification of nanostructures on page-3)
Nanofilms, Nanoplates and Nanonetwork: 2D structures which
have been named on basis of their shape (refer identification of
nanostructures on page-3)
Graphene: sp2 hybridised cyclic structures containing double
bonds having strength higher than even diamond.
Nanosponge: 3D structures which are porous in nature (having
pores and cavities in nanometre range)
Nanocomposites:3D structures which are formed by piling of
nanoparticles in bulk
Graphite: Aggregates of graphene arranged in layer fashion.
Diamond: sp3 hybridised carbon molecules arranging themselves
to form a crystal structure

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TEM microscope (Transmission electron microscope relies on a
beam of electrons for the formation of an image of the specimen;
it can have measure objects less than 100 nm with precision)
 Summary:
We can classify nanomaterials based on two different
parameters:
1. We can classify them on basis of number of dimensions
lying outside the nanoscale region- 0D,1D,2D and 3D.
2. We can classify them on basis of the way nanoparticles can
be formed- top-down method and bottom-up method
 Acknowledgement:
I would like to state that except pictures which have been taken
from Google images, everything has been written and made by
me. This assignment is plagiarism-free.