Simulating charge transport in tris(8-hydroxyquinoline) aluminium (Alq 3)

J. J. Kwiatkowski, J. Nelson, H. Li, Jean-Luc Bredas, W. Wenzel, C. Lennartz

Research output: Contribution to journalArticlepeer-review

155 Scopus citations

Abstract

We present a model of charge transport in organic solids which explicitly considers the packing and electronic structure of individual molecules. We simulate the time-of-flight mobility measurement in crystalline and disordered films of tris(8-hydroxyquinoline) aluminium (Alq3). The morphology of disordered Alq3 is modelled on a molecular scale, and density functional theory is used to determine the electronic couplings between molecules. Without any fitting parameters we predict electron mobilities in the crystalline and disordered phases of ∼1 and ∼10-4 cm 2 V-1 s-1, respectively. In good agreement with experiment we find that electron mobilities are two orders of magnitude greater than those of holes. We explain this difference in terms of the spatial extent of the frontier orbitals. Our results suggest that charge transport in disordered Alq3 is dominated by a few highly conducting pathways.

Original languageEnglish (US)
Pages (from-to)1852-1858
Number of pages7
JournalPhysical Chemistry Chemical Physics
Volume10
Issue number14
DOIs
StatePublished - Apr 1 2008

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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