Carrier hopping in disordered semiconducting polymers: How accurate is the Miller-Abrahams model?
We performed direct calculations of carrier hopping rates in strongly disordered conjugated polymers based on the atomic structure of the system, the corresponding electronic states and their coupling to all phonon modes. We found that the dependence of hopping rates on distance and the dependence of the mobility on temperature are significantly different than the ones stemming from the simple Miller-Abrahams model, regardless of the choice of the parameters in the model. A model that satisfactorily describes the hopping rates in the system and avoids the explicit calculation of electron-phonon coupling constants was then proposed and verified. Our results indicate that, in addition to electronic density of states, the phonon density of states and the spatial overlap of the wavefunctions are the quantities necessary to properly describe carrier hopping in disordered conjugated polymers.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); Computational Research Division
- DOE Contract Number:
- DE-AC02-05CH11231
- OSTI ID:
- 993855
- Report Number(s):
- LBNL-4018E; APPLAB; TRN: US201024%%174
- Journal Information:
- Applied Physics Letters, Vol. 97, Issue 4; ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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