Molecular orientation and optical luminescence properties of soluble star shaped oligothiophene molecules for organic electronic applications

Regan G. Wilks, Gap Soo Chang, Kyung Hwan Kim, Dong Hoon Choi, Alexander Moewes

Research output: Contribution to journalArticle

2 Citations (Scopus)


Angle resolved near-edge absorption fine structure measurements of the C 1s edge of a film of the star-shaped molecule 4(HPBT) show a high degree of order, with the molecules maintaining a largely planar geometry in an upright configuration. X-ray excited optical luminescence measurements showed a dependence of the luminescence spectrum on the excitation energy, with (0-0), (0-1), and (0-2) vibrational modes being clearly visible when exciting off-resonance; the appearance of these features under off-resonance is attributed to a scattering process that is quenched when the excitation approaches a core absorption resonance. The HOMO-LUMO gap is estimated from the luminescence measurements (2.28 eV), and this value is confirmed by the comparison of the C 1s absorption and C Kα emission spectra.

Original languageEnglish
Pages (from-to)355-359
Number of pages5
JournalJournal of Electron Spectroscopy and Related Phenomena
Issue number7
Publication statusPublished - 2011 Jul 1



  • Soft X-ray emission spectroscopy
  • XEOL

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Radiation
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Spectroscopy
  • Physical and Theoretical Chemistry

Cite this