1. Alabama A&M University, Normal, AL USA
MWCNT Doped PVDF: Nanocomposite Films and Their Raman Spectral Analysis
Presenter: Dr. Padmaja “Paddy” Guggilla
Alabama A&M University, Normal, AL USA
August 22, 2016
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2. Outline Objectives Implementation Results Conclusions Acknowledgements
Introduction and Background
Objectives
Implementation
Results
Conclusions
Acknowledgements
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3. Pyroelectricity
Pyroelectricity is the ability of certain materials to generate an electrical potential when they are heated or cooled.
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4. Pyroelectric Material Characteristics
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5. Advantages of Pyroelectric Detectors
♦ Sensitivity in a very large spectral bandwidth
♦ Sensitivity in a very wide temperature range without need of cooling
♦ Use at room temperature
♦ Low power requirement
♦ Relatively Fast Response
♦ Low-cost material
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6. Principle of Pyroelectric Infrared Detector
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7. Basic Pyroelectric Detector Element
Incident
Radiation A d
Output
Signal
Thin Film
Electrodes 
Pyroelectric
Material
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Cartoons created by Dr. James Currie Jr.

8. Pyroelectric Detector Aplications
Environmental applications
Mineral exploration, pollution monitoring, detecting volcanic eruptions, Climate control
Medical applications
Respiratory monitors, infrared thermal imaging, Anesthesiology gas monitoring
Military applications
Motion detectors, thermal sensors, detection of missiles or aircrafts, night vision goggles
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9. Composite Thin Films Trending research topic Popular choice Flexible
Easy to fabricate
Cost effective
Can be used for many different applications
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10. Lead-Free Thin Films No more toxic Lead-based compounds!
Lead-Free compounds
Environmentally friendly
Safer for human use
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11. Doping of Materials To enhance or tune the material properties.
To meet the stringent requirements for various applications.
Leads to the creation of vacancies and interstitials which minimize the stress of the lattice.
Defects produced by atoms have no preferential direction and are randomly distributed throughout the material.
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12. A Few Materials Investigated
Polyvinylidenedifluoride (PVDF)
Lithium Niobate (LiNbO3)
Barium Titanate (BaTiO3 )
Lithium Tantalate (LiTaO3)
Lithium Tantalate Doped with MWCNT
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13. PVDF Polyvinylidene fluoride Ferroelectric polymer when poled
Outstanding properties
High mechanical strength
Thermal stability
Chemical resistance
β –phase
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14. Raman Spectroscopy
Measures the relative frequencies at which a sample scatters radiation
Raman scattering
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15. Fabrication of the Thin Films
MEK/DMF+PVDF solution Add Nanocomposite Material Magnetic Stirrer and Hot Plate Dry in Furnace Thin Film
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16. Fabrication of the Thin Films
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17. PVDF Pyroelectric Current Yield
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18. PVDF:BaTiO3 Pyroelectric Current Yield
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19. PVDF:LiNbO3 Pyroelectric Current Yield
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20. PVDF:LiTaO3 Pyroelectric Current Yield
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21. PVDF, BaTiO3, LiNbO3 and LiTaO3 Pyroelectric Current Yield
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22. PVDF, BaTiO3,LiNbO3 and LiTaO3 Pyroelectric Current Yield
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23. Raman Spectrum of PVDF
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24. Raman Spectrum of PVDF+BaTiO3
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25. Raman Spectrum of PVDF+LiNbO3
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26. Raman Spectrum of PVDF+LiTaO3
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27. Raman Spectrum of PVDF+LiTaO3+MWCNT
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28. Dielectric, Pyroelectric and Figures-of-Merit of PVDF and Composites Films
Temp
(⁰C)
Pyroelectric Coeff (nC/cm² ⁰C)
Dielectric
Contant
Loss
Pyroelectric-voltage (V)
FMV=p/ ε′
(nC/cm² ⁰C)
FMvid=p/( ε′)1/2
PVDF Film 35
0.1175
12.924
0.4702
3.16
.00909
.03271 45
0.4345
13.540
0.7785
3.31
.02975
.10458 55
2.0943
14.378
1.1059
3.51
.13759
.52346 65
7.4164
15.093
1.5894
3.69
.45585
2.0942 75
28.302
16.026
2.1629
3.92
1.7665
7.0674
PVDF:MWCNT Film
63.971
26.175
12.329
10.19
2.4564
99.137
31.115
17.245
12.12
3.2943
189.07
36.578
24.985
14.24
5.4329
394.56
42.897
37.487
16.70
9.7286
968.41
49.767
55.724
19.38
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29. Conclusions
Lead-free nanocomposite thin films were fabricated successfully using the low cost solution casting technique.
All the nanocomposite thin films that were characterized for their electrical and optical properties.
Among the pure PVDF and PVDF:BaTiO3, PVDF:LiNbO3, and PVDF:LiTaO3 nanocomposite films PVDF:LiTaO3 generated the maximum pyroelectric current
Doping of the Lead-free pyroelectric materials will enhance the pyroelectric properties of the material which is evident in the data shown.
Lithium Tantalate doped with MWCNT would be a great alternate as a smart material and Raman spectrum shows the characteristic peak of MWCNT C-C bonds in the film fabricated.
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30. Acknowledgements
This work has been supported DHS-BS Award #2010-ST
Ms. Kourtney Walker for her assistance with sample preparation and measurement monitoring.
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31. Thank You for Your Time
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