Abstract
Knowledge of the full phonon spectrum is essential to accurately calculate the dynamic disorder (σ) and hole mobility (μh) in organic semiconductors (OSCs). However, most vibrational spectroscopy techniques under-measure the phonons, thus limiting the phonon validation. Here, we measure and model the full phonon spectrum using multiple spectroscopic techniques and predict μh using σ from only the Γ-point and the full Brillouin zone (FBZ). We find that only inelastic neutron scattering (INS) provides validation of all phonon modes, and that σ in a set of small molecule semiconductors can be miscalculated by up to 28% when comparing Γ-point against FBZ calculations. A subsequent mode analysis shows that many modes contribute to σ and that no single mode dominates. Our results demonstrate the importance of a thoroughly validated phonon calculation, and a need to develop design rules considering the full spectrum of phonon modes.
Original language | English |
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Pages (from-to) | 5530–5537 |
Number of pages | 8 |
Journal | Journal of Physical Chemistry Letters |
Volume | 13 |
Issue number | 24 |
Early online date | 13 Jun 2022 |
DOIs | |
Publication status | Published - 23 Jun 2022 |
Keywords
- organic semiconductors
- phonon validation
- inelastic neutron scattering