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(1) : University of Sannio, Optoelectronic Division -Engineering Department, Benevento - Italy. (2) : Department for Technologies, University Parthenope, Napoli, Italy. (3) : ENEA, Materials and New Technologies, CR Brindisi, Brindisi - Italy. - PowerPoint PPT Presentation
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Ischia, 21-23 giugno 2006Riunione Annuale GE 2006
Optoelectronic Division - Engineering Department
University of Sannio, Benevento – Italy
Sensori Chimici in Fibra Sensori Chimici in Fibra OtticaOttica
basati su Nanotubi di basati su Nanotubi di CarbonioCarbonio
M. Consales1, M. Pisco1, S.Campopiano2, A. Cutolo1, M. Penza3, P. Aversa3,
M. Giordano4, A. Cusano1
(1): University of Sannio, Optoelectronic Division -Engineering Department, Benevento - Italy.
(4): Institute for Composite and Biomedical Materials, CNR, Napoli, Italy.
(2): Department for Technologies, University Parthenope, Napoli, Italy
(3): ENEA, Materials and New Technologies, CR Brindisi, Brindisi - Italy.
POSTER # A27POSTER # A27
Ischia, 21-23 giugno 2006Riunione Annuale GE 2006
Optoelectronic Division - Engineering Department
University of Sannio, Benevento – Italy
Silica Optical Fiber (SOF) SensorsFor an important number of environmental monitoring and industrial applications fiber-optic sensor technology offers several advantages for significant metrological improvement through:
The scientific community is interested in:
High sensitivity
Immunity to electromagnetic interference
Safety in the corrosive environments
Fast response
This technology is suitable for distributed measurements and it is, by definition, compatible with the fiber-optic communication networkscompatible with the fiber-optic communication networks
New devices able to provide high performance sensing mechanism and multiplexing capability.
Ischia, 21-23 giugno 2006Riunione Annuale GE 2006
Optoelectronic Division - Engineering Department
University of Sannio, Benevento – Italy
Principle of OperationPrinciple of Operation
ΔΔRRfilmfilm=f (=f ( ΔΔεεFilmFilm , , ΔΔddFilmFilm))
•Rfilm is the fiber-film reflectance
•εSWCNTs= ε1+jε2 is the dielectric constant of
the film
• dSWCNTs is the film thickness
When the optical probe is exposed to a target analyte, its molecules are When the optical probe is exposed to a target analyte, its molecules are adsorbed within the sensitive layer, changing its thickness and adsorbed within the sensitive layer, changing its thickness and
complex dielectric function and thus the optical signal reflected at the complex dielectric function and thus the optical signal reflected at the fiber film interface.fiber film interface.
Pinc
Pref
Single-mode optical fiber SWCNTs sensitive layer
Pinc
Pref
Single-mode optical fiber SWCNTs sensitive layer
Ischia, 21-23 giugno 2006Riunione Annuale GE 2006
Optoelectronic Division - Engineering Department
University of Sannio, Benevento – Italy
Why Single-Walled Carbon Nanotubes (SWCNTs)?Why Single-Walled Carbon Nanotubes (SWCNTs)?
Carbon nanotubes are basically sheets of graphite
rolled up into a tube to form a cylinder.
• Peculiar hollow structure
• Diameters in the range 1-10 nm
• High specific surface area (100-1800 m2/g)
• Particular interactions between carbon atoms and gas molecules
Ischia, 21-23 giugno 2006Riunione Annuale GE 2006
Optoelectronic Division - Engineering Department
University of Sannio, Benevento – Italy
Langmuir-Blodgett (LB) deposition techniqueLangmuir-Blodgett (LB) deposition technique
HiPco SWCNTs (purchased by CNI) films have been deposited
monolayer by monolayer by successively dipping the substrates up and
down through the monolayer
Ischia, 21-23 giugno 2006Riunione Annuale GE 2006
Optoelectronic Division - Engineering Department
University of Sannio, Benevento – Italy
Structural and morphological CNTs characterizationStructural and morphological CNTs characterizationSEM image of SWCNTs bundlesSEM image of SWCNTs bundles XRD from SWCNTs powderXRD from SWCNTs powder
HRTEM image of SWCNTs bundlesHRTEM image of SWCNTs bundles
Low magnificationLow magnification
HRTEM image of SWCNTs bundlesHRTEM image of SWCNTs bundles
High magnificationHigh magnification
•Mean rope diameter: 1-40 nmMean rope diameter: 1-40 nm
• Mean rope length: 2-15 Mean rope length: 2-15 µm µm
• Monolayers spacing ~ 2.0 nmMonolayers spacing ~ 2.0 nm
Ischia, 21-23 giugno 2006Riunione Annuale GE 2006
Optoelectronic Division - Engineering Department
University of Sannio, Benevento – Italy
Volatile Organic Compounds (VOCs) detection Volatile Organic Compounds (VOCs) detection
Standard Silica Optical Fiber coated by 4 monolayers of SWCNTs (approx. 8nm)
120 180 240 300 360
0.76
0.77
0.78
0.79
0.80
Time (min)
54 ppm
64 ppm
73 ppm
Op
to
electro
nic S
ig
na
l
93 ppm TOLUENE
120 180 240 300 360 420 480
0.765
0.770
0.775
0.780
0.785
0.790
0.795
0.800
Time (min)
3 ppm
7 ppm
O
ptoelectron
ic S
ign
al (
A.U
.)
17 ppm
22 ppm
27 ppm
39 ppm XYLENE
Response of a Carbon Nanotubes based SOF sensor to different concentrations of (a) toluene and (b) xylene vapors, at room
temperature.
XYLENE VAPORSXYLENE VAPORS
Resolution of approx. 120 ppb
Response times (10%-90%) of approx. 11 minutes
Recovery times (90%-10%) of approx. 6 minutes
TOLUENE VAPORSTOLUENE VAPORS
Resolution of approx. 290 ppb
Response times (10%-90%) of approx. 9 minutes
Recovery times (90%-10%) of approx. 5 minutes
Ischia, 21-23 giugno 2006Riunione Annuale GE 2006
Optoelectronic Division - Engineering Department
University of Sannio, Benevento – Italy
Hollow-core Optical Fibers (HOFs) based chemical Hollow-core Optical Fibers (HOFs) based chemical sensorssensors
180 240 300 3602.580
2.583
2.586
2.589
Op
toel
ectr
onic
Sig
nal
(A
.U.)
Time (min)
184 ppm
200 ppm
291 ppm
TetraHydroFuran
Response of the photonic band-gap fiber based sensor to three decreasing concentration of THF
vapors, at room temperature.
Images of a photonic band-gap optical Images of a photonic band-gap optical fiber without and with SWCNTsfiber without and with SWCNTs
HOF coated by 20 monolayers of SWCNTs for TetraHydroFuran
(THF) vapors detection
Ischia, 21-23 giugno 2006Riunione Annuale GE 2006
Optoelectronic Division - Engineering Department
University of Sannio, Benevento – Italy
Hydrogen Detection at Criogenic TemperaturesHydrogen Detection at Criogenic Temperatures
120 140 160 180 200 220 240 260
0.485
0.486
0.487
0.488
0.489
0.490
0.491
0.492
0.493
0.494
Hydrogen off
Opt
ical
res
pons
e (A
.U.)
Time (min)
Hydrogen on at lower concentration
Hydrogen off
Hydrogen on
T=-160°C
Response of a Carbon Nanotubes based optical fiber sensor to two different concentration of gaseous
hydrogen, at -160°C.
Ischia, 21-23 giugno 2006Riunione Annuale GE 2006
Optoelectronic Division - Engineering Department
University of Sannio, Benevento – Italy
THANKS FOR YOUR THANKS FOR YOUR
ATTENTIONATTENTION