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Ultrafast Photoconductivity in Organic Semiconductors

Published online by Cambridge University Press:  01 February 2011

Oksana Ostroverkhova ,
David G. Cooke ,
Frank A. Hegmann ,
John E. Anthony ,
Vitaly Podzorov ,
Michael E. Gershenson ,
Oana D. Jurchescu  and
Thomas T.M. Palstra
Oksana Ostroverkhova
Affiliation:
oksana@physics.orst.edu, Oregon State University, Physics, 301 Weniger Hall, Corvallis, OR, 97331, United States
David G. Cooke
Affiliation:
dcooke@phys.ualberta.ca, University of Alberta, Physics, Edmonton, T6G 2J1, Canada
Frank A. Hegmann
Affiliation:
hegmann@phys.ualberta.ca, University of Alberta, Physics, Edmonton, T6G 2J1, Canada
John E. Anthony
Affiliation:
anthony@uky.edu, University of Kentucky, Chemistry, Lexington, 40506, United States
Vitaly Podzorov
Affiliation:
podzorov@physics.rutgers.edu, Rutgers University, Piscataway, 08854, United States
Michael E. Gershenson
Affiliation:
gersh@physics.rutgers.edu, Rutgers University, Piscataway, 08854, United States
Oana D. Jurchescu
Affiliation:
jurchescu@chem.rug.nl, University of Groningen, Groningen, N/A, 9747, Netherlands
Thomas T.M. Palstra
Affiliation:
t.t.m.palstra@rug.nl, University of Groningen, Groningen, N/A, 9747, Netherlands
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Abstract

We present comprehensive study of ultrafast charge carrier dynamics in a variety of organic molecular crystals. In all samples, we observed sub-picosecond charge photogeneration and band-like transport, characterized by (i) an increase in charge carrier mobility as the temperature decreases in a wide temperature range of at least 20 K – 300 K and (ii) mobility anisotropy in the a-b plane of the crystals. The temperature dependence of the decay dynamics of the transient photoconductivity reveals the presence of shallow trapping sites in herring-bone-type-structured crystals (such as pentacene (Pc), tetracene (Tc), and rubrene (Rub)), while such traps are apparently absent in “brick-wall”-type crystals (such as functionalized pentacene (FPc)). We also report on the measurements of the charge carrier mobility anisotropy in the a-b plane of two types of FPc single crystals. Anisotropies of approximately 3.5 and 11.6 were obtained in the crystals characterized by crystal structures favoring two-dimensional and one-dimensional charge transport, respectively, consistent with the degree of π-overlap along different directions in the crystals.

Keywords

photoconductivityorganicelectronic material
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 935: Symposium K – Materials Research for THz Applications , 2006 , 0935-K03-07
Copyright
Copyright © Materials Research Society 2006

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References

1 Hegmann, F. A, Ostroverkhova, O., and Cooke, D. G, “Probing Organic Semiconductors with Terahertz Pulses”, in Photophysics of molecular materials, edited by Lanzani, G. (Wiley-VCH, Weinheim, 2006), pp. 367–428.Google Scholar
2 Ostroverkhova, O., Cooke, D. G, Shcherbyna, S., Egerton, R. F, Hegmann, F. A, Tykwinski, R. R, and Anthony, J. E, Phys. Rev. B 71, 035204 (2005).Google Scholar
3 Ostroverkhova, O., Shcherbyna, S., Cooke, D. G, Egerton, R. F, Hegmann, F. A, Tykwinski, R. R, Parkin, S. R, and Anthony, J. E., J. Appl. Phys. 98, 033701 (2005).Google Scholar
4 Ostroverkhova, O., Cooke, D. G, Hegmann, F. A, Anthony, J. E, Podzorov, V., Gershenson, M. E, Jurchescu, O. D, and Palstra, T. T. M., Appl. Phys. Lett. 88, 162101 (2006).Google Scholar
5 Anthony, J. E, Brooks, J. S, Eaton, D. L, and Parkin, S. R, J. Am. Chem. Soc. 123, 9482 (2001).Google Scholar
6 Hegmann, F. A and Lui, K. P. H., Proc. of SPIE 4643, 31 (2002).Google Scholar
7 Hegmann, F. A, Tykwinski, R. R, Lui, K. P. H., Bullock, J. E, and Anthony, J. E, Phys. Rev. Lett. 89, 227403 (2002).Google Scholar
8 Moses, D., Sinclair, M., and Heeger, A. J, Phys. Rev. Lett. 58, 2710 (1987).Google Scholar
9 Anthony, J. E, Eaton, D. L, and Parkin, S. R, Org. Lett 4, 15 (2002).Google Scholar
10 Karl, N., “Charge-carrier mobility in organic crystals”, in Organic Electronic Materials, eds. Farchioni, R. and Grosso, G. (Springer, 2001), pp.283–322.Google Scholar