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Crossover from Hopping to Band-Like Charge Transport in an Organic Semiconductor Model: Atomistic Nonadiabatic Molecular Dynamics Simulation
- Source :
- The Journal of Physical Chemistry Letters, The Journal of Physical Chemistry Letters, 2018, 9 (11), pp.3116-3123. ⟨10.1021/acs.jpclett.8b01112⟩
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Abstract
- The mechanism of charge transport (CT) in a 1D atomistic model of an organic semiconductor is investigated using surface hopping nonadiabatic molecular dynamics. The simulations benefit from a newly implemented state tracking algorithm that accounts for trivial surface crossings and from a projection algorithm that removes decoherence correction-induced artificial long-range charge transfer. The CT mechanism changes from slow hopping of a fully localized charge to fast diffusion of a polaron delocalized over several molecules as electronic coupling between the molecules exceeds the critical threshold V ≥ λ/2 (λ is the reorganization energy). With increasing temperature, the polaron becomes more localized and the mobility exhibits a "band-like" power law decay due to increased site energy and electronic coupling fluctuations (local and nonlocal electron-phonon coupling). Thus, reducing both types of electron-phonon coupling while retaining high mean electronic couplings should be part of the strategy toward discovery of new organics with high room-temperature mobilities.
Details
- Language :
- English
- ISSN :
- 19487185
- Volume :
- 9
- Issue :
- 11
- Database :
- OpenAIRE
- Journal :
- The Journal of Physical Chemistry Letters
- Accession number :
- edsair.pmid.dedup....e46df2bd948415f605b4656824ec5291
- Full Text :
- https://doi.org/10.1021/acs.jpclett.8b01112