Self-ordering properties of functionalized acenes for annealing-free organic thin film transistors

Paul Bazylewski, Kyung Hwan Kim, Dong Hoon Choi, Gap Soo Chang

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


Presented here is a study of the molecular self-ordering properties of four bis(phenylethynyl) anthracene based organic semiconductors related to their electronic structure employing X-ray spectroscopy techniques and density functional theory (DFT) calculations. The local molecular order through polarization dependence of C 1s → π* transitions revealed ordered π-stacking nearly perpendicular to the substrate due to van der Waals interactions between alkyl groups. DFT calculations were used to deconvolute the measured electronic structure and examine effects of small changes in molecular geometry in relation to measured charge carrier mobility in top contact field effect transistors. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) are found to be conjugated from the anthracene core across the bridging ethynyl groups to the thiophene and phenyl end groups. The inclusion of ethynyl bridges connecting the thiophenes has a twofold effect of both reducing the rotational freedom of this functional group and increasing HOMO/LUMO conjugation across the molecules. These features help create a more rigid upright structure for HB-ant-THT with better molecular orbital conjugation and subsequent higher mobility. With this understanding of how different functional groups interact with an acene core, future synthesis of new materials may be directed toward annealing-free organic semiconducting materials.

Original languageEnglish
Pages (from-to)10658-10664
Number of pages7
JournalJournal of Physical Chemistry B
Issue number36
Publication statusPublished - 2013 Sept 12

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry


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