Optical Anisotropy and Momentum-Dependent Excitons in Dibenzopentacene Single Crystals
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Contributors
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 language | English |
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Pages (from-to) | 21183-21191 |
Number of pages | 9 |
Journal | ACS omega |
Volume | 7 |
Issue number | 24 |
Publication status | Published - 21 Jun 2022 |
Peer-reviewed | Yes |