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Nanomaterial characterization techiniques by kunsa h. of ethiopia
1. 1
ADAMA SCEINCE AND TECHNOLOGY
UNIVERSITY
FACULTY OF APPLIED SCIENCES
DEPARTMENT OF APPLIED PHYSICS
Course Title: synthesis and characterizations of
nanoparticles [Phys8111]
Assignment-1
By: Kunsa Haho ID: pgr/01947/12
Adama, Ethiopia
December , 2012 E.C
2. 2
Outline of presentation
Fourier-transform infrared spectroscopy (FTIR)
Thermoluminescence (TL)
Four point probe DC/AC measurements
Magnetic properties measuring system
Cyclic voltammetry and galvanostic charge–
discharge methods
3. The objective of presentation
To present my understanding of above
described techniques of nanomaterials
characterization, specially on
The basic working principle
The primary data to be obtained
The analysis method of data by each
techniques
3
4. Spectroscopy – the study of the interaction of light with
matter.
Infrared Spectroscopy – the study of the interaction of
infrared light with matter.
Mid-Infrared – light from 4000 to 400 wave numbers
(cm−1 ).
Spectrum – a plot of measured light intensity versus some
property of light such as wavelength or wave number.
Spectrometer – an instrument that measures a spectrum.
Infrared Spectrometer – an instrument that measures an
infrared spectrum.
FTIR – Fourier Transform Infrared, a specific type of
infrared spectrometer
1.Fourier-transform infrared
spectroscopy (FTIR)
5. I. The basic working principle
Fourier Transform Infrared Spectroscopy
(FT-IR) is often used in the analysis of
functional group structural changes and new
species present on nanoparticles or
nanoparticle-based material surfaces.
FTIR measures the absorption of IR radiation by
each bond in the molecule and as a result gives
spectrum which is commonly designated as %
transmittance versus wavenumber (cm−1).
5
6. basic working principle….
A diverse range of materials containing
the covalent bond absorbs
electromagnetic radiation.
The IR region is at lower energy and
higher wavelength than the UV-visible
light and has higher energy or shorter
wavelength than the microwave
radiations.
6
7. basic working principle….
For the determination of functional groups,
molecule must be IR active.
An IR active molecule is the one which has
dipole moment. When the IR radiation
interacts with the covalent bond of the
materials having an electric dipole, the
molecule absorbs energy, and the bond starts
back and forth oscillation.
Therefore, the oscillation which causes the
change in the net dipole moment of the
molecule should absorb IR radiations. 7
8. basic working principle….
For example:
A single atom doesn’t absorb IR radiation as it
has no chemical bond.
Symmetrical molecules also do not absorbed IR
radiation, because of net zero dipole moment
(like H2,O2 )
On the other hand:- HF,CH4, C2H6, NO2, TiO2
are some of IR active molecules.
8
9. basic working principle….
Note that a particular IR radiation (frequency)
will be absorbed by a particular bond in the
molecule, because every bond has their
particular natural vibrational frequency.
For example : acetic acid (CH3COOH)
containing various bonds (C-C, C-H, C-O, O-H,
and C=O), all these bonds are absorbed at
specific wavelength and are not affected by
other bond.
Two molecules with different structures don’t
have the same infrared spectrum. 9
12. basic working principle….
FTIR spectroscopy is an advanced and
extensively used analytical tool that
investigates the structural chemistry of the
sample by irradiating with IR radiations.
The molecules or sample absorb the IR
radiations and display an absorption
spectrum.
FT-IR measures the absorption of various IR
light wavelengths by the sample of interest
and gives the percentage of transmission
12
13. In an FTIR instrument, the Fourier
transform converts the intensity
versus optical path difference (i.e
interferogram ) to the intensity
versus wavenumber ussually the
percent transmittance /absorbance
versus wavenumber
13
14. Fig. FT-IR spectra of (a) fresh titanyl sulfate, (b) titanyl sulfate
dried at 350◦C for 1 hour, and (c) as-milled powder
14
18. Components of FTIR
spectroscope
Infrared Light Source
The infrared light source generates wide
band radiation by heating solid materials
to incandescence using electric power.
commonly two IR sources are used:
1.Nernst glower, which is composed of
mainly oxides of rare-earth elements
2.Globar, which is composed of silicon
carbide. 18
19. Most IR sources are operated at the
temperature where the maximum energy
of radiation is near the short wavelength
limit of the IR spectrum.
19
20. Beam-splitters: should be made of
material semi-transparent to infrared light
which should reflect one half portion of
infrared light to the moving mirror while
transmitting the rest infrared to a fixed
mirror.
The most common beam-splitter is a
sandwich structure, with a thin layer of
germanium (Ge) between two pieces of20
21. The infrared detector is a device to measure
the energy of infrared light from the sample
being examined. It functions as a transducer to
convert infrared light signals to electric signals.
There are two main types:
1.the thermal detector
2.the semiconductor detector.
The key component in a thermal detector is a
pyroelectric crystal, of which the most commonly
used type is deuterated triglycine sulfate (DTGS)21
22. The most commonly used semiconductor
detector is made of mercury cadmium
telluride (MCT).
An MCT detector absorbs infrared photons
which in turn causes the electrons to migrate
from the valence band to the conduction band
of the semiconductor.
The electrons in the conduction band generate
electric current signals. The MCT detector is up to
10 times more sensitive than the DTGS type
22
23. Its dis advantage is that
it detects a narrower band of radiation
(4000–700 cm−1).
It needs to be cooled, commonly to liquid
nitrogen temperature (−196 ◦C), before
operation.
it saturates easily with high intensity
radiation.
23
24. Summary of data analysis
techiniques by FTIR spectroscopy
24
27. f.g.FT-IR analysis was performed for gold
nanoparticles biosynthesized using the extracts
of Tamarindus indica L leaves (Correa et al.
2016
27
28. Functional groups in the leaf
extracts of T. indica included
carbonyl compounds (1716.54 cm-1),
aromatic rings (1559.37 cm-1)
nitro compounds (1540.32 cm-1),
alkanes (1394.81 cm-1),
alkenes (1650.19 cm-1),
amines (1254.59 cm-1),
Alcohols(3307.91,1126.74,1072.36 cm-1),
phosphates (1072.36 cm-1), and
alkyl halides(557.22 cm-1)
28
29. Advantages and dis- advantage of
FTIR Specrtoscopy
One of main advantages of FTIR spectroscopy
is its capability to identify functional groups
such as C=O, C-H, or N-H.
FTIR spectroscopy enables by measuring all
types of samples: solids, liquids, and gases
Disadvantage is that , the commercial FTIR
instruments operate only to in medium IR
region; therefore some molecular vibration in
lower frequency cannot be observed.
29
30. 2.Thermoluminescence
(TL)
I. The basic working principle
Thermoluminescence (TL) is a technique to
measure the intensity of luminescence of a
sample when it is irradiated by UV radiation, X-
rays, γ-rays, or an electron beam as a function
of temperature.
Thermoluminescence (TL) is defined as the
emission of light from a semiconductor or an
insulator when it is heated, due to the previous
absorption of energy from irradiation.
30
34. Figure 2. Simple two-level model for thermoluminescence. Allowed
transitions: (1) ionization; (2) and (5) trapping; (3) thermal release;
(4) radiative recombination and the emission of light. Electrons are
the active carriers, but an exactly analogous situation arises for
holes. Electrons, solid circles; electron transitions, solid arrows;
holes, open circles; hole transitions, open arrows. 34
38. 38
F.g.shows the typical TSL glow curves of as-formed CeO2
nanoparticles exposed to γ-rays for a dose range of 1–4 kGy
recorded at a heating rate of 5°C s− 1. TL studies revealed well-
resolved glow peak at 224°C with a small shoulder at 131°C. The TL
glow peak intensity increases linearly with γ-rays’ dose, which
suggests CeO2 nanoparticles were suitable for radiation dosimetry
applications
39. 3.Four point probe DC/AC
measurements
I. DC measurements :-there are two types of dc
conductivity measurement techiniques
A.Two point probe method :-a known d.c potential is applied
across a cell, (in which electrolyte material is
sandwiched between two perfectly reversible
electrodes) and the resulting current is measured,
simply to determine the d. c. resistance.
Two-point probe technique may determine the voltage
drop from a simple measurement by using a
conventional a Digital multimeter.
But in the case of semiconductors and thin films, the
interpretation of the results is often difficult 39
40. Four point probe method: a known d.c. current is
applied between two outer electrodes and the
potential is measured across two inner electrodes.
Figure. Four-Point Collinear Probe Resistivity Method 40
43. Introduce a geometric correction factor F for most practical samples
ρ=2 πFsFs(V
I )
44. 44
AC measurements
Impedance spectroscopic technique is used to
measure Ac current of the sample.
A sinusoidal voltage signal of low amplitude is applied
across a solid electrolyte cell and the resulting current
through the cells determined.
Generally, this current is related to the voltage in two
ways viz.
I. the ratio of the current and voltage maxima,
(analogous to resistance in D.C measurements) and;
II. the phase difference between voltage and current.
The combination of (i) and (ii) gives the impedance 'Z'
of the cell
45. The most common and standard method is to apply a
sinusoidal ac voltage of small amplitude(Vo, 1–200 mV) and
single frequency v = ω/2π and measure the phase shift θ
and amplitude Io of the resulting current at that frequency
described as
V (t) =V O∗eiωtωtt
∧ I (t )=I O∗eiωt (ωtt+θθ )
This procedure is repeated for different frequencies, in the range
between about 1 mHz and 1 MHz. From the obtained voltage V(t) and
current I(t), the impedance Z(ω) is obtained as a complex parameter
Z=
V ( t )
I ( t )
=
V o
I 0
∗e− iωtθ
=Z real +θiωtZ iωtmag
46. 46
The results of the complex impedance measurement of a
material as a function of applied signal frequency can be
displayed conventionally in a complex plane any in one of the
following form of equations:
48. Some of the magnetic property
measuring instruments in
nanomaterials are
SQUID Magnetometry
Mössbauer Spectroscopy
Neutron Powder Diffraction
Lorentz Microscopy
Vibrating Sample Magnetometer (VSM)
Electron Spin Resonance
Ferromagnetic Resonance
Nuclear Magnetic Resonance --etc
The magnetic properties of materials are usually
determined by studying the response of materials to
an applied magnetic field. 48
49. SQUID (acronym for Superconducting
Quantum Interference Device)
magnetometry
The SQUID magnetometer is arguably the most
popular type of magnetometers.
It has the distinction of being the most
sensitive magnetometer.
The working mechanisms of the SQUID are
based on two fundamental principles
I .superconductivity i.e.quantization of the
magnetic flux in a superconducting ring
(Gallop, 1990).
II.The Josephson effect 49
54. Fi.g.Left: Au nanoparticles having diameters of 2.5 nm and
coated with poly-vinylpyrrolidone (PVP) and Right:Au
nanoparticles having diameters of 2.1 nm and coated with thiol
derivatives
54
55. f.g.Magnetization versus applied field for Au and Pd
nanoparticles having diameters of 2.5 nm and coated
with polyvinylpyrrolidone (PVP) ref:kumar,magnetic
characterization
55
56. Vibrating Sample Magnetometer (VSM)
The instrument is based on the principle that an oscillatory
magnetic field can be created by vibrating a magnetic
sample.
Magnetization in the sample is induced by applying a
uniform magnetic field (0-2.5T)to the sample.
58. Electron spin resonance
spectrometry
Electron spin resonance spectrometry
(ESR) is a technique that can give
information about unpaired electrons in
materials.
In the presence of a magnetic field, the
two spin states of a lone electron lose
their degeneracy.
The electron can be resonantly driven
between the two spin states with an RF
wave. 58
64. Mössbauer Spectroscopy
64
Mössbauer spectroscopy is an absorption
technique in which a nucleus is probed by gamma
rays.
When the energy transitions are between the
energy states of a nucleus, and the photons are in
the γ-ray region, such resonant absorption is
known as Mössbauer spectroscopy
Typically, three types of nuclear interactions are
observed:
Isomer shift (or chemical shift),
Quadrupolar splitting, and
Hyperfine splitting (Zeeman splitting)
65. Isomer shift is related to the electron charge
density in the s orbital
Quadrupolar splitting reflects the influence of
surrounding field gradients and nuclear energy levels.
Magnetic splitting (hyper-fine splitting) results by the
interaction between the nucleus and local magnetic
field.
66. Neutron Powder Diffraction
This most powerful tool for magnetic material
characterization.
Neutrons may interact with both the nucleus and
the nuclear magnetic moment in the lattice.
This gives rise to diffraction reflections from both
the crystal structure and the magnetic order of the
sample
Neutron powder diffraction can provide the
magnetic structural information in addition to the
crystalline phases
The neutron beam is produced by either a nuclear
reactor source or a spallation source
67. Fig. Neutron diffraction pattern (λ = 1.4991 Å) of CoFe2O4
nanoparticles at 523 K. Below the pattern, the first row of sticks
marks the peaks from the magnetic scattering. The second row
of sticks marks the peaks from nuclear scattering
69. Voltammetryis the study of current as a function of applied
potential and is a category of electroanalytical methods
used in analytical chemistry
There are numerous forms of voltammetry
• Potential Step(pulsed potential)
• Linear sweep
• Cyclic Voltammetry
Cyclic Voltammetry:In this case the voltage is swept
between two values at a fixed rate, however now when the
voltage reaches V2 the scan is reversed and the voltage
is swept back to V1
70. Fig. Voltage as a function of time and current as a function of
voltage for Cyclic voltametry
71. CV is a potential sweep method where the potential of an
electrode, which is immersed in an unstirred solution, is varied
and the corresponding current is measured
In cyclic voltammetry the potential of an electrode (or
voltage of a system) is changed linearly between two potential
extremes and then returned to the initial potential.
The current that passes during this potential cycle is
recorded as a function of the potential. The rate at which the
potential is changed is called the sweep rate (u).
Cyclic Voltammograms (CVs) are the resulting current
versus potential plots complete the cycle as shown in fig
above
72. Type of electrodes used in electrochemical cell
Indicator electrode:-The electrode whose potential is
a function of the analyte’s concentration (also known as
the working electrode):use glassy carbon,Pt and Au
Counter electrode:-The second electrode in a two-
electrode cell that completes the circuit. Use pt wire
Reference electrode:An electrode whose potential
remains constant and against which other potentials
can be measured.use Ag/AgCl
74. In galvanostatic (or constant current)
charge/discharge experiments,a known set current (I) is
applied to an electrode and the potential is recorded over
time.
This method is a reliable method to evaluate the
electrochemical capacitance of materials under controlled
current conditions.
This technique is very different from cyclic voltammetry
because the current is controlled and the voltage is
measured.
This is indeed one of the most widely used techniques in
the field of supercapacitor because it can be extended from
a laboratory scale to an industrial one.
Galvanostatic charge
discharge method
75. Fi.g.Schematic diagram of a galvanostat charge discharge set up
R = resistor; i = galvanometer; A = auxiliary electrode; W =
working electrode; R = reference electrode; V = voltmeter or
potentiometer (optional).
76. This method is also called as chronopotentiometry
and gives access to various parameters such as:
Capacitance
Resistance
Cyclability
In this method, a current pulse is applied to the working
electrode and the resulting potential is measured against a
reference electrode as a function of time.
When the electrode reaches a desired potential, the
current direction is changed (the same current but opposite
in sign is now applied) and again the potential is recorded.
Often, the potential will be cycled between these two
potential limits.
78. Fourier infrared spectroscopy
1.Infrared Spectroscopy:Fundamentals and Applications
2.Haghi, A. K.Zachariah, Ajesh K.Kalarikkal, Nandakumar – Nanomaterials
3.Sulabha K. Kulkarni (auth.) - Nanotechnology Principles and Practices
4.Ramiro P.rez.Campos,Antonio Contreras Cuevas,materials
characterization
Thermoluminescence
1.Macveer ,Thermoluminiscence of solids
2.Sulabha K. Kulkarni (auth.) - Nanotechnology Principles and Practices
Four point Dc/Ac measurements
Magnetic Measurements
1.Sulabha K. Kulkarni (auth.) - Nanotechnology Principles and Practices
2.Janos H. Fendler Nanoparticles and Nanostructures
Cyclic voltametery and galvanoistatic charge discharge
1.Janos H. Fendler Nanoelectrochemistry
References
![1
ADAMA SCEINCE AND TECHNOLOGY
UNIVERSITY
FACULTY OF APPLIED SCIENCES
DEPARTMENT OF APPLIED PHYSICS
Course Title: synthesis and characterizations of
nanoparticles [Phys8111]
Assignment-1
By: Kunsa Haho ID: pgr/01947/12
Adama, Ethiopia
December , 2012 E.C](https://image.slidesharecdn.com/nanomaterialcharacterizationtechiniquesbykunsah-200507133203/85/Nanomaterial-characterization-techiniques-by-kunsa-h-of-ethiopia-1-320.jpg)
