Optical Anisotropy and Momentum-Dependent Excitons in Dibenzopentacene Single Crystals

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Lukas Graf - , Chair of Experimental Solid State Physics, Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • Fupin Liu - , Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • Marco Naumann - , Chair of Road Planning and Road Design, Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • Friedrich Roth - , TU Bergakademeie Freiberg, Freiberg University of Mining and Technology (Author)
  • Bipasha Debnath - , Chair of Experimental Solid State Physics, Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • Bernd Büchner - , Chair of Experimental Solid State Physics, Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • Yulia Krupskaya - , Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • Alexey A. Popov - , Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • Martin Knupfer - , Leibniz Institute for Solid State and Materials Research Dresden (Author)

Abstract

High-quality single crystals of the organic semiconductor (1,2;8,9)-dibenzopentacene were grown via physical vapor transport. The crystal structure─unknown before─was determined by single-crystal X-ray diffraction; polarization-dependent optical absorption measurements display a large anisotropy in the ac plane of the crystals. The overall Davydov splitting is ∼110 meV, which is slightly lower than that in the close relative pentacene (120 meV). Momentum-dependent electron energy-loss spectroscopy measurements show a clear exciton dispersion of the Davydov components. An analysis of the dispersion using a simple 1D model indicates smaller electron- and hole-transfer integrals in dibenzopentacene as compared to pentacene. The spectral weight distribution of the excitation spectra is strongly momentum-dependent and demonstrates a strong momentum-dependent admixture of Frenkel excitons, charge-transfer excitons, and vibrational modes.

Details

Original languageEnglish
Pages (from-to)21183-21191
Number of pages9
JournalACS omega
Volume7
Issue number24
Publication statusPublished - 21 Jun 2022
Peer-reviewedYes

Keywords