Hostname: page-component-586b7cd67f-gb8f7 Total loading time: 0 Render date: 2024-11-25T15:43:28.630Z Has data issue: false hasContentIssue false
  • English
  • Français

Imaging individual chains and aggregates on conjugated polymer films

Published online by Cambridge University Press:  15 February 2011

M. Kemerink ,
J.K.J. van Duren ,
P. Jonkheijm ,
P.M. Koenraad ,
R.A.J. Janssen ,
H.W.M. Salemink  and
J.H. Wolter
M. Kemerink
Affiliation:
Depts. of Applied Physics and Chemical Engineering
J.K.J. van Duren
Affiliation:
Laboratory of Macromolecular and Organic Chemistry
P. Jonkheijm
Affiliation:
Laboratory of Macromolecular and Organic Chemistry
P.M. Koenraad
Affiliation:
COBRA Inter-University Research Institute Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands
R.A.J. Janssen
Affiliation:
Depts. of Applied Physics and Chemical Engineering Laboratory of Macromolecular and Organic Chemistry
H.W.M. Salemink
Affiliation:
COBRA Inter-University Research Institute Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands
J.H. Wolter
Affiliation:
COBRA Inter-University Research Institute Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands
Get access

Abstract

We demonstrate a novel method to visualize individual molecular chains in the surface layer of organic semiconducting polymer films of arbitrary thickness. The method is based on scanning force microscopy and employs a combination of a sensitive phase detection system and metal coated tips with a low (∼1 N/m) spring constant and a relatively high Q factor (∼200). The molecularly resolved morphology is observed in phase images that are taken simultaneously with the topography. Surprisingly, we found that, when the tip apex radius exceeds the intermolecular spacing in the surface layer, surface aggregates –when present- are visualized. In both cases, the phase contrast is shown to result from van der Waals interaction between the conjugated backbone of the polymer chains and the metallic tip, and can quantitatively be described by a simple harmonic oscillator model. We have employed this method to study the morphology of poly(p-phenylene vinylene) (PPV) derivatives with different substitutions.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 771: Symposium L – Organic and Polymeric Materials and Devices , 2003 , L3.4
Copyright
Copyright © Materials Research Society 2003

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

[1] Cornil, J., Beljonne, D., Calbert, J.-P., Brédas, J.-L., Adv. Mater. 2001, 13, 1053.Google Scholar
[2] Nguyen, T.-Q. et al., J. Phys. Chem. B 2001, 105, 5153.Google Scholar
[3] Tan, C.H., Inigo, A.R., Hsu, J.-H., Fann, W., Wei, P.K., J. Phys. Chem. Sol. 2001, 62, 1643.Google Scholar
[4] Blatchford, J.W. et al., Phys. Rev. B 1996, 54, 3683.Google Scholar
[5] Sirringhaus, H. et al., Nature 1999, 401, 685.Google Scholar
[6] Hassenkam, T., R, D..Greve, Bjørnholm, T., Adv. Mater. 2001, 13, 631.Google Scholar
[7] Martens, H. C. F., Blom, P. W. M., Schoo, H. F. M., Phys. Rev. B 2000, 61, 7489.Google Scholar
[8] Other interactions have also been considered. In particular, the Coulomb force between charge on the sample, either fixed or induced by the work function difference between tip and sample, with the metallic tip can be of equal strength as the van der Waals force. Nevertheless, this can be excluded since the bias dependence predicted by such models is not observed.Google Scholar
[9] Hamaker, H.C., Physica 1937, IV, 1058.Google Scholar
[10] Boer, E.A. et al., J. Appl. Phys. 2001, 90, 2764.Google Scholar
[11] Argento, C. and French, R.H., J. Appl. Phys. 1996, 80, 6081.Google Scholar
[12] HyperChem Molecular Modeling System, Hypercube, Inc. Google Scholar
[13] Kittel, C., in Introduction to solid state physics, 6th ed., Wiley, New York 1986.Google Scholar
[14] Sutherland, D.G.J. et al., Appl. Phys. Lett. 1996, 68, 2046.Google Scholar