Unification of trap-limited electron transport in semiconducting polymers

H. T. Nicolai, M. Kuik, G. A.H. Wetzelaer, B. De Boer, C. Campbell, C. Risko, J. L. Brédas, P. W.M. Blom*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

306 Scopus citations

Abstract

Electron transport in semiconducting polymers is usually inferior to hole transport, which is ascribed to charge trapping on isolated defect sites situated within the energy bandgap. However, a general understanding of the origin of these omnipresent charge traps, as well as their energetic position, distribution and concentration, is lacking. Here we investigate electron transport in a wide range of semiconducting polymers by current-voltage measurements of single-carrier devices. We observe for this materials class that electron transport is limited by traps that exhibit a Gaussian energy distribution in the bandgap. Remarkably, the electron-trap distribution is identical for all polymers considered: the number of traps amounts to 3 × 1023 traps per m3 centred at an energy of ∼3.6 eV below the vacuum level, with a typical distribution width of ∼0.1 eV. This indicates that the electron traps have a common origin that, we suggest, is most likely related to hydrated oxygen complexes. A consequence of this finding is that the trap-limited electron current can be predicted for any polymer.

Original languageEnglish (US)
Pages (from-to)882-887
Number of pages6
JournalNature Materials
Volume11
Issue number10
DOIs
StatePublished - Oct 2012

ASJC Scopus subject areas

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

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