P3HT Nanowire formation in solution
Epitaxial Growth of Poly(3-hexylthiophene) on Carbon NanotubesJianhua Liu, Jianhua Zou and Lei Zhai*
NanoScience Technology Center, Department of Chemistry, University of Central Florida, 12424 Research Parkway Suite 400, Orlando, FL 32826
Orange Purple
Nanofibrils
dispersion @ RT
P3HT
hot solution
Cooling to RT
in marginal solvents
500 nm 50 nm
Marginal solvents: anisole, cyclopentanone, etc.
Width=12-15 nm; Length=1-10 μm; Height=3-7 nm
Length
Heig
ht
P3HT
Thermochromism
Figure 1. TEM images of P3HT nanowires obtained
via a solution method.
Pristine Carbon nanotubes (CNTs) dispersed by P3HT
Figure 2. TEM images of SWCNTs (A) and MWCNTs (B)
dispersed by P3HT in chloroform. (Scale bar: 200 nm )
P3HT nanowire formation induced by CNTs (epitaxial growth)
Figure 4. TEM images of P3HT supramolecular structures
on MWCNTs (A and C) and SWCNTs (B and D).
(Scale bar: A, B = 1μm, C, D = 100 nm)
Width: 12~15 nm.
Length: from tens to hundreds nm.
Height: 3-5 nm
Figure 5. Tapping-mode AFM height images (top)
and cross sections of the line trace (bottom) of P3HT
supramolecular structures on MWCNTs (A) and
SWCNTs (B)
Length control of P3HT nanowires on CNTs
Hierarchal P3HT/CNT supramolecular structures were
fabricated through a CNT induced P3HT crystallization
strategy.
The length of P3HT nanowires on CNTs can be controlled
by tuning the P3HT/CNT mass ratio.
The quasi-isothermal crystallization process monitored by
in-situ UV-Vis spectroscopy indicates the CNT nucleation
effect and the first-order kinetics of P3HT nanowire growth.
This bottom-up strategy provides a general approach to
build functional conductive supramolecular structures on
CNTs
300 400 500 600 700 8000.0
0.4
0.8
1.2
Absorb
ance
Wavelength nm
SWCNTs
MWCNTs
Kinetics Study by UV-Vis (Quasi-isothermal process )
Acknowledgments: NSF CAREER award DMR 0746499
Figure 7. In situ UV-Vis monitored isothermal P3HT nanowire formation at room temperature ([P3HT] = 0.05 mg/mL,
P3HT/CNT=7; A: without CNTs; B: with MWCNTs; C: with SWCNTs), and UV-Vis absorbance change at 600 nm of
the P3HT suspension during the monitored process (D; Solid lines are the fitted first-order kinetics curves).
Figure 6. TEM images of P3HT nanowires formed on SWCNTs at different P3HT/ SWCNT mass ratio of 40
(A); 22 (B); 10 (C); 5 (D). (Scale bar: 200 nm)
Conclusions
References
P3HT: Mn=14800, PDI=1.2; Regioregularity = 96%
Figure 3. UV-Vis absorption spectra of MWCNTs and
SWCNTs dispersion.
[SWCNT] = 0.008 mg/mL
[MWCNT] = 0.008 mg/mL
Dispersed CNTs were added into P3HT anisole solutions as nucleation seeds to grow P3HT nanowires.
A B
A B
DC
Centipede-like morphology
A B
A B
P3HT nanowires on MWCNTs are affected by the nanotube diameter and surface curvature. MWCNTs with large
diameter and less surface curvature have a higher density of nanowires.
P3HT nanowires on SWCNTs are more uniform because SWCNTs are straight with similar diameters.
MWCNTs Vs SWCNTs
Length of P3HT nanowires can be controlled by tuning the P3HT/CNT mass ratio.
300 400 500 600 700
0.0
0.5
1.0
1.5
2.0
Ab
so
rba
nce
Wavelength nm
0
10 min
30 min
1 h
2 h
4 h
12 h
24 h
40 h
300 400 500 600 700
0.5
1.0
1.5
2.0
2.5
Ab
so
rba
nce
Wavelength nm
0
5 min
15 min
30 min
1 h
1.5 h
2 h
3 h
300 400 500 600 700
0.5
1.0
1.5
2.0
Absorb
ance
Wavelength nm
0
6 min
15 min
30 min
45 min
1 h
2 h
0 20 40
0.0
0.2
0.4
0.6
With MWCNTs
Time (h)
Absorb
ance c
hange
Without CNTs
With SWCNTs
A B C D
1. Liu, J.; Zou, J.; Zhai, L. Macromol. Rapid. Commun. 2009, 30, 1387-1391.
2. Zou, J.; Liu, L.; Chen, H.; Khondaker, S. I.; McCullough, R. D.; Huo, Q.; Zhai, L. Adv. Mater. 2008, 20, 2055-2060.
3. Ihn, K. J.; Moulton, J.; Smith, P. J. Poly. Sci. B: Poly. Phys. 1993, 31, 735-742.
4. Li, L.; Li, C. Y.; Ni, C. J. Am. Chem. Soc. 2006, 128, 1692-1699.
Figure 8. Schematic illustration of hierarchal 2D P3HT/CNT
supramolecular structures
455 nm: π-π* electronic transition of isolated P3HT chain in solution
510, 550 and 600 nm: π-π* electronic transition and a strong lattice vibration of P3HT in solid state
Pronounced nucleation effect of CNTs and first order kinetics of P3HT nanowire growth
