Ultrafast photoconductivity in organic semiconductors

Oksana Ostroverkhova, David G. Cooke, Frank A. Hegmann, John E. Anthony, Vitaly Podzorov, Michael E. Gershenson, Oana D. Jurchescu, Thomas T.M. Palstra

Research output: Chapter in Book/Report/Conference proceedingConference contribution


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"-π-stacked 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.

Original languageEnglish (US)
Title of host publicationMaterials Research for THz Applications
PublisherMaterials Research Society
Number of pages6
ISBN (Print)1558998926, 9781558998926
StatePublished - 2006
Event2006 MRS Spring Meeting - San Francisco, CA, United States
Duration: Apr 17 2006Apr 21 2006

Publication series

NameMaterials Research Society Symposium Proceedings
ISSN (Print)0272-9172


Other2006 MRS Spring Meeting
Country/TerritoryUnited States
CitySan Francisco, CA

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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