Carbon Nanotubes: Synthesis and Functionalization L. Valentini L. Valentini Materials Engineering Centre, INSTM, UdR Perugia Materials Engineering Centre, INSTM, UdR Perugia - - Universit Universit à à di Perugia, di Perugia, Loc. Pentima Loc. Pentima Bassa Bassa - - Terni Terni Website: Website: http://www.unipg.it/materials http://www.unipg.it/materials
25
Embed
Carbon Nanotubes: Synthesis and Functionalizationacletters.org/procs/1st_workshop/abstracts/lectures/valentini... · Carbon Nanotubes: Synthesis and Functionalization L. Valentini
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Carbon Nanotubes: Synthesis and Functionalization
L. ValentiniL. Valentini
Materials Engineering Centre, INSTM, UdR Perugia Materials Engineering Centre, INSTM, UdR Perugia -- UniversitUniversitààdi Perugia, di Perugia,
Defects in CNTsDefects in CNTs1Point defects such as Point defects such as
vacanciesvacanciesTopological defects caused Topological defects caused by forming pentagons and by forming pentagons and heptagons e.g. 5heptagons e.g. 5--77--77--5 5 defectdefectHybridization defects Hybridization defects caused due to caused due to functionalization
Ibridizzazione sp31
functionalization
10 nm
1Ref: S Namilae et. al. (2001)
Defects in CNTsDefects in CNTs
1200 1400 1600 1800
SWNTs
Inte
nsity
[arb
. uni
ts]
Wavenumber [cm-1]
F. Mercuri et al., J. Phys. Chem. B (submitted)
Role of Interfaces in CompositesRole of Interfaces in Composites
Critical issues in nanotube compositesCritical issues in nanotube composites–– DispersionDispersion
Load transfer effected by interface characteristicsLoad transfer effected by interface characteristicsInterfaces further affect electrical propertiesInterfaces further affect electrical propertiesInterface Interface Bounding surface with physical / Bounding surface with physical / chemical / mechanical discontinuitychemical / mechanical discontinuity–– Strengthening of interfaces in conventional Strengthening of interfaces in conventional
compositescompositesChemical reactionChemical reactionSurface asperities on fiberSurface asperities on fiber
In CNT composites In CNT composites chemical attachmentschemical attachments
M. Grujicic et al., AppliedSurface Science 206 (2003)
167
R. Pati et al., APL 81 (2002) 2638
500 1000 1500 2000 2500 3000 3500 4000
(d,e)(c)(b)
(a)
Abs
orba
nce
[arb
. uni
ts]
Wavenumber [cm-1]
FTIR spectra obtained under exposure to H2O without (a) an electrical field and at different frequencies (b) 1 Hz, (c) 100 Hz, (d) 1
KHz and (e) 1 MHz (1V ac excitation wave).
The IR spectra obtained at different frequencies under exposure to H2O show that the transparency tends to decrease when increasing the applied frequency. The results obtained suggest that the main contribution to the
interaction between water vapor molecules and the nanotube is associated to adsorbate-dipole/nanotube-dipole interactions.
L. Valentini et al., Diamond and Related Materials 14 (2004) 121.
The NanoChan ProjectThe NanoChan ProjectNano Channel Template: fabrication of a photovoltaic device.
TWO nanotechnologies involved:
1. Nanochannels built in the self-assembled CNTs template with regular and uniform pattern
2. Carbon nanotubes grown by self-assembling on Pt electrodes
Optimize CN properties in order to use themas charge collectors between an activemedium and the readout electronics and study the coupling
Optical Window
R/O electronics
Basic idea
NanotubeNanotube arrayarray
NanoNano--heterohetero--junctionsjunctions
Si
Ligth
Channels for charges
transportation
n-type a-C:H(F) nanochannel
p-type CNTs array
Plasma CF4
Substrate Si
-3 -2 -1 0 1 2 31E-101E-91E-81E-71E-61E-51E-41E-3
a-C:H:F/CNTsCur
rent
[A/c
m2 ]
Voltage [V]
CONCLUDING REMARKSCONCLUDING REMARKS
☺ Research on nanotubes and nanowires show much interesting science with potential for applications☺ Attaching chemical groups to the sidewall of CNTs to modify the properties as needed for applications
Chemical modification of the sidewall may improve the adhesion characteristics of CNTs in a host matrix to make compositesChemical or photosensors
☺ Fluorination of SWNTs with CF4 gas has been shown to attach F covalently to the sidewall☺ Cold plasma approach to functionalization
BUT
Major challenges still exist:- Low material cost, - High durability,- Control of materials properties,- Self-assembly of large numbers of components.
SEM - TEM, Raman, Synthesis of PAMAMProf. S. Russo (Dip. di Chimica e Chimica Industriale, Università di Genova)Dr. Laura Ricco (Dip. di Chimica e Chimica Industriale, Università di Genova)Dr. Jenny Alongi (Dip. di Chimica e Chimica Industriale, Università di Genova)Dr. A. Mariani (Dip. Di Chimica, Universitàdi Sassari)
AcknowledgmentsTGA - FTIRDr. D. Puglia (Dip. di Dip. di Ingegneria Ingegneria CivileCivile e e AmbientaleAmbientale, , Università di PerugiaUniversità di Perugia)Dr. I. Armentano (Dip. di Dip. di Ingegneria Ingegneria CivileCivile e e AmbientaleAmbientale, , Università di PerugiaUniversità di Perugia)Dr. J. Macan (Sveuciliste u Zagrebu)
Funding:Ministry of Education, University and Research through the PRIN, FIRB projectsThe National Consortium of Materials Science and Technology (INSTM)
e-BEAM LithographyDr. G. Pennelli (Dip. di Ingegneria dell' Informazione: elettronica, informatica, telecomunicazioni, Università di Pisa)
Molecular DynamicProf. A. Sgamellotti (Dip. di Chimica, ISTM – CNR, Università di Perugia)Dr. F. Mercuri (Dip. di Chimica, ISTM –CNR, Università di Perugia)