Experimental study of encapsulated molecules inside carbon

Experimental study of
encapsulated molecules
inside carbon nanotubes
2nd year of a jointed PhD Thesis between L2C and ILL
Ana Carolina LOPES SELVATI
Jean-Louis BANTIGINES, Rozenn LE PARC L2C UM/CNRS
Stéphane ROLS TOF/HR ILL
All you need is neutrons, S02E03 27th october 2015
Carbon Nanotubes (NTs)
NTs: bundle-like structure
NTs are closed-end
after synthesis
Oxydation treatment:
open NTs
http://www.iws.fraunhofer.de/en/pressandmedia/press_releases/2012/press_release_2012-04.html
1
Nature Mat. 2007, 6, 183
Motivation
NT
In order to tune this Egap,
We need a hybrid NT.
Encapsulation of:
4TCH3
Egap of NTs at infrared region
Adv. Mater. 2010, 22, 1635-1639
2
Hybrid system: encapsulation
Dymethyl-quaterthiophene
(4TCH3)
encapsulation
High temperature treatment
NTφ:
Mean diameter (Å) of the distribution of diameters of the sample
3
What we already know about it?
20
18
16
-1
ΔωRBM (cm )
14
1 chain
2 chains in 2 chains More than 2
interaction
chains
one with
the other
12
10
8
6
4
2
0
-2
0,6 0,7 0,8 0,9 1,0 1,1 1,2 1,3 1,4 1,5 1,6 1,7 1,8 1,9 2,0
Diamètre (nm)
Adv. Mater. 2010, 22, 1635-1639
4
J. Phys. Chem. C, 2014, 118(33) 19462-19468
Before neutrons
What we would like to know?
—  To probe the encapsulation of the molecule inside
the nanotube.
—  What is the influence of the confinement in the
molecule which is encapsulated inside the NT?
—  Is there any possible interaction between the
encapsulated molecule and the NT?
5
Encapsulation of the molecule
300
NT14
Intensity (a.u.)
250
200
(10)
150
100
(11)
(20)
(21)
(22) and (31)
50
0
0
3
6
9
12
15
18
21
24
2θ (°)
6
Science, 1996, 273, 483
Encapsulation of the molecule
TEM
30 0
4T@NT14
25 0
Intensity (a.u.)
4T@NT14
NT14
20 0
(10)
15 0
10 0
(11)
(20)
(21)
(22) a nd (31)
50
0
0
3
6
9
12
15
18
21
24
2θ (°)
7
J. Phys. Chem. C, 2014, 118(33) 19462-19468
Influence of the confinement on the 4TCH3
N T 0 9
4 T C H 3
4 T C H 3 @ N T 0 9
N T 0 9
660nm
λ
300nm
1400
1425
1450
1475
1500
1525
1550
-1
R a m a ns hift(c m )
Resonance of the encapsulated 4TCH3
8
Efficiency of the charge transfer
electron donor
-
PL
= signal
Photoluminescence of
semi-conducting NTs
Diameter of probed NTs
Charge transfer is more intense for small diameter NTs
9
Before neutrons
Conclusion
—  The molecules of 4TCH3 are
encapsulated inside carbon
nanotubes;
—  The molecules absorb in their
optical window;
—  The charge transfer from the
Effects of confinement
By tuning the size of the confining
matrix, we can probe the confinement
of the molecule…
molecule to the carbon
nanotube was evidenced.
10
4TCH3@NTφ
Charge transfer and confinement effects:
Probed by Photoluminescence, Raman spectroscopy
x-ray Diffraction.
Those effects influenciate the molecular vibrations.
Lets probe it by means of Inelastic Neutron
Spectroscopy.
11
Inelastic Neutron Scattering: Principle
In order to probe molecular motions:
nuclear scattering
130meV
—  Conditions to be fulfilled:
—  Momentum conservation
—  Energy conservation
12
Vibrational properties of confined 4TCH3
Inelastic neutron scattering
Carbon Sulfur Hydrogen
Total scattering cross section (barn) 5.551
1.026 82.02
HPDOS: Hydrogen Partial Density of States
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Vibrational properties of confined 4TCH3
Inelastic neutron scattering
Carbon Sulfur Hydrogen
Total scattering cross section (barn) 5.551
1.026 82.02
HPDOS: Hydrogen Partial Density of States
14
Probing molecular motions
IN4c
IN1-Lagrange
15
IN4c
Time-of-flight spectrometer
16
IN1-Lagrange
Filter analyser spectometer
17
Approach: couple experiments and DFT
experimental data
measured at 2K
simulated data
Simulated HPDOS calculated by A. Belhboub
18
Simulated HPDOS by DFT
—  Calculs DFT carried out by Anouar Belhboub:
—  SIESTA; Non-conservative pseudo-potential (PSP).
4TCH3
Isolated
molecule
4TCH3@(11,0)
φ=0.86nm
4TCH3@(17,0)
φ=1.33nm
19
Simulated HPDOS calculated by A. Belhboub
Treatment of the simulated HPDOS
—  Performed in three parts:
—  1- Convolution with the
instrument’s resolution
function.
—  2- Debye-Waller
contribution
—  3- Multi-phonon
contribution
Simulated HPDOS calculated by A. Belhboub
20
Resolution function of the instrument
IN1-Lagrange
IN4c
IN1-Lagrange
IN4c
Simulated HPDOS calculated by A. Belhboub
21
Debye-Waller factor
HPDOS
+1
Approximation:
—  Low temperature
—  Large energy transfer
Simulated HPDOS calculated by A. Belhboub
22
Multi-phonon expansion
elastic term one-phonon term
Simulated HPDOS calculated by A. Belhboub
Multi-phonon expansion
23
MP procedure details in: Physica B 1999, 271, 212-222
Results
Small
Medium
Large
measured at 2K
Simulated HPDOS calculated by A. Belhboub
24
Small energy transfer
Error bars removed for the sake of clarity
Simulated HPDOS calculated by A. Belhboub
25
Medium energy transfer
Simulated HPDOS calculated by A. Belhboub
26
Large energy transfer
391meV
367meV
Simulated HPDOS calculated by A. Belhboub
27
Preliminary conclusions
—  There is no signature of the bulk molecule in the
hybrid system.
—  The same tendency is observed for both: the
experiments as well as the simulations:
confinement effect.
Now, lets talk about technical issues that I have had!
28
Water adsorbed by NTs
September 2015
May 2015
@ 2K in IN1-Lagrange
29
Phys. Rev. Lett. 2003, 90, 195503
Technical issues discussion
2nd: Instrument’s calibration
1st: Instrument’s resolution
3nd: energy transfer shift
30
IN1-Lagrange resolution
Monochromator: Cu(220)
31
IN4c and IN1-Lagrange: calibration
32
IN1-Lagrange: Energy transfer shift
4TCH3
measured in
two different
beam-times!
33
Acknowledgements
Yann Almadori
Monica Jimenez-Ruiz
Laurent Alvarez
Anouar Belhboub
Fernando Torres
Stéphane Campidelli
Raymond Aznar
Bruno Jousselme
Philippe Dieudonné
Pascal Puech
David Maurin
Thierry Michel
Said Tahir
34
Any questions?
35
Thank you for your
attention!
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