Molecular-weight-dependent mobilities in regioregular poly(3-hexyl- thiophene) diodes

Chiatzun Goh*, R. Joseph Kline, Michael D. McGehee, Ekaterina N. Kadnikova, Jean M.J. Fŕchet

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

407 Scopus citations


We have investigated the transport properties in the direction perpendicular to the substrate of regioregular poly(3-hexyl-thiophene) of different molecular weights (MW) in a diode geometry. In these devices, which exhibit space-charge-limited behavior, we find that the mobility values at room temperature increase from 1.33× 10-5 cm2 V s to 3.30× 10-4 cm2 V s as the MW is increased from 2.9 to 31.1 kgmol. The mobility is found to be field independent for high MW films, but field dependent for the low MW films. The current-voltage characteristics of the diodes are also studied as a function of temperature from 160 K to 300 K. The activation energy for carrier transport, extracted from the Arrhenius plot, is found to decrease gradually from 143 meV to 126 meV as the MW is increased.

Original languageEnglish (US)
Article number122110
Pages (from-to)1-3
Number of pages3
JournalApplied Physics Letters
Issue number12
StatePublished - Mar 21 2005
Externally publishedYes

Bibliographical note

Funding Information:
The authors thank A. Salleo from PARC for help with and access to their probe station setup. This work was supported in part by a Kodak Research Fellowship, the Center on Polymer Interfaces and Macromolecular Assemblies at Stanford University, and the Air Force office of Scientific Research and the Department of Energy, Basic Energy Sciences.

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


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