PROPERTIES OF NANOMATERIALS

1. DEPARTMENT OF CHEMISTRY AND CHEMICAL SCIENCES
PRESENTATION TOPIC:-PROPERTIES OF NANOMATERIALS
PRESENTED TO:-DR. SHIWANI BERRY.
PRESENTED BY:-KANUPRIYA (M.SC. CHEMISTRY 3rd sem.)
ROLLNO.:- CUHP19CCS11.

2. PROPERTIES OF NANOMATERIALS

4. Properties transformation from
Bulk to Nano
Nano properties depend on the size of the nano-
clusters that constitute the material and the change
that occur are -
1. Opaque substances becomes transparent e.g:-
Copper. Grain size reduces to 1-100nm
2. Inert materials become catalyst e.g.:-Silicon.
3. Nanomaterials are exceptionally strong, hard,
ductile at high temperature.
4. Materials become wear resistant, corrosion
resistant and chemically very active.

5. PROPERTIES AFFECTED BY
NANOSIZE
OPTICAL MAGNETIC CHEMICAL
MECHANICAL ELECTRICAL

6. Optical Properties Of
Nanomaterials
SEMICONDUCTOR
NANOPARTICLES
METALLIC
NANOPARTICLES

7. OPTICAL PROPERTIES OF
NANOMATERIALS
•Nanoscale dimension
(In semiconductor
nanoparticles).
•Surface plasmon
resonance
(In metal nano-particles).
1) The optical properties of
nanomaterials depends upon:-
• Nanoscale dimension of particle
and
• Surface plasmon resonance.
2) These properties are strongly
influenced by a number of factors
such as –size, shape, surface
functionalization, doping and
interactions with other materials

8. ENERGY BAND DIAGRAM

9. SEMICONDUCTOR
NANOPARTICLES
1. QUANTUM SIZE CONFINEMENT EFFECT.
2. BLUE SHIFT.
3. EFFECT OF DOPING.

10. QUANTUM SIZE CONFINEMENT EFFECT
1) On decreasing the size of material- the
electrons gets confined to the
particle(confinement effect) leading to:-
•Increase in band gap energy and
•Band levels gets quantized(discrete).
2) Surface states(trap states) which lie in the
band gap becomes important alter the optical
properties of nanomaterials.
3) The energy level spacing increases with
decreasing dimension known as “QUANTUM
SIZE CONFINEMENT EFFECT.
4) Absorbance is strongly affected by the size
of nanoparticle.

12. Difference between CONTINUOUS and
QUANTIZED Energy levels

13. EFFECT OF SIZE REDUCTION ON BAND GAP
ENERGY

15. BLUE SHIFT- With reducing the size of the particle the density of states becomes
more quantized and the band gap shifts to higher energies(shorter wavelength) which means the
absorption spectrum shows a blue shift.

17. TUNABLE BAND GAP – b/w 1.7 to 3.1 eV we can get any colour from
nanoparticles by tuning the energy levels i.e. by changing the no. of particles of same
material in nanomaterial cluster.

18. EFFECT OF DOPING ON OPTICAL PROPERTIES
OF SEMICONDUCTOR NANOMATERIALS on doping
we can make transitions of electrons by low wavelength incident photons and obtain the desired
colour.

19. METAL NANOPARTICLES
SURFACE PLASMON
RESONANCE
EFFECT OF
SURROUNDING MEDIUM
(on surface plasmon
resonance)

20. METAL NANOMATERIAL
• In metals we don’t have band gap so the colour of a bulk metals are black in colour or
are very shiny, but in nano size metal particles colloidal solution you will see coloured
solution even for metal particles. But the absorption is not the same as in
semiconducting nanoparticles because metals don’t have a band gap. So what is this
colour in metals due to. So if u look at metal nano particles there is a property known as
SURFACE PLASMON RESONANCE, which occurs especially if your nanoparticles are
metallic.
• The colour depends on the size ,shape of the particle and the dielectric properties of
the medium.
• Surface plasmons are excited by the incident electromagnetic radiations and surface
plasmons have lower energy than the bulk plasmons.

22. Condition for surface plasmon resonance to occur-the polarizability i.e.
“alpha” should be minimum i.e.’0’ and it occurs only when the dielectric constant of the metal
becomes equal to the negative of the dielectric constant of the medium.

23. Change in frequency from bulk to nanoparticles- for surface
plasmon resonance to occur.

28. MAGNETIC PROPERTIES
OF NANAOMATERIALS

29. Transformation In Magnetic Properties
from BULK To NANO
• FERRO and FERRIMAGNETIC BULK
MATERIALS –becomes
superparamagnetic in nano size.
• ANTIFERROMAGNETIC BULK
MATERIALS – becomes weakly
ferromagnetic in nano size.

30. REASON FOR DOMAIN FORMATION IN FERROMAGNETC
BULK MATERIALS- is to minimize magnetostatic
energy(i.e., energy stored in static magnetic field)
Domain formation when bulk is placed in
magnetic field

31. BULK TO NANO MAGNETIC MOMENT CHANGE

32. Degradation of DOMAIN WALL on reduction of size in
Ferromagnetic Bulk Material

33. DECREASE IN MAGNETISATION WITH REDUCTION
IN SIZE OF A MATERIAL.
IN BULK IN NANOMATERIALS

34. BLOCKING TEPMERATURE-Transition temperature where you
should be getting ferromagnetism but you start getting
superparamagnetism from a ferromagnetic material

35. Magnetic Properties Of Antiferromagnetic
Nanomaterials
In metal oxides –
1) In case of bulk substance there are core
and surface electrons and magnetic
properties are mainly determined by the
core electrons.
2) Whereas in case of nanomaterial from the
same material –the core has been
degraded or reduced(as the size of the
nanoparticles is too small)due to which
there remains only the surface electrons
and these surface electrons are easily
affected by the magnetic field and thus
make the nanoparticles weakly
ferromagnetic in nature.
e.g. CuO , NiO etc.

36. SIZE DEPENDENCE- Different solvents produces different sizes nanoparticles of
same material and thus affects the magnetic properties of the metal oxides.

37. In ANTIFERROMAGNETIC NANOMATERIALS - magnetic
properties are due to the uncompensated electrons i.e. surface dominated
electrons.

39. CHEMICAL PROPERTIES
1.)Chemical properties include the elemental
composition of nanomaterials and its surface
chemistry such as zeta potential and
photocatalytic properties.
2.)The chemical properties of a materials are
determined by the type of motion of its
electrons.
3.)There is a wide range of nanoparticles
contributing to many different chemical
properties-
•QUANTUM DOTS.
•METALLIC NANOPARTICLES .

41. QUANTUM DOTS
1) Structurally quantum dots consists of large
no. of metal complexes such as
semiconductors, metals and magnetic
transition metals.
2) The bioactivity of quantum dots can be
improved by suitable surface coating with
biocompatible material .
3) Depending on their size ,it fluoresces
different colours and QD’s composed of
cadmium selenide core wrapped in zinc
sulfide shell is such of a kind.

43. METALLIC NANOPARTICLES
• The attraction of surface excitons for
the application typically arises from the
large electromagnetic field
enhancement near the metal surface
and dependence of the resonance
wavelength on the size, shape and local
dielectric properties of nanoparticles.

44. APPLICATIONS
• Platform Material for biomolecular ultrasensitive detection.
• Hyperthermal treatment of cancer cell.
• Protein labelling and targeted delivery of the therapeutic agents with
in the cells.