Insights into the charge carrier terahertz mobility in polyfluorenes from large-scale atomistic simulations and time-resolved terahertz spectroscopy

0382730 - FZÚ 2013 RIV US eng J - Journal Article
Vukmirović, N. - Ponseca, C.S. - Němec, Hynek - Yartsev, A. - Sundström, V.
Insights into the charge carrier terahertz mobility in polyfluorenes from large-scale atomistic simulations and time-resolved terahertz spectroscopy.
Journal of Physical Chemistry C. Roč. 116, č. 37 (2012), s. 19665-1972. ISSN 1932-7447. E-ISSN 1932-7455
Institutional research plan: CEZ:AV0Z10100520
Keywords : charge carrier mobility * time-resolved terahertz spectroscopy * multiscale atomistic calculations
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 4.814, year: 2012

Multiscale atomistic simulations were used to understand the factors that determine the far-infrared charge carrier mobility spectrum in conjugated polymers. The simulation approach combines classical molecular dynamics simulations of atomic structure, large-scale electronic structure calculations, and the evaluation of the THz mobility using Kubo's linear response formula. We found that THz radiation probes a single carrier hop at low temperatures and high frequencies, while the transport over somewhat longer distances is probed in the opposite cases. Our results indicate that charge carrier transport at THz frequencies is thermally activated but with a much smaller activation energy compared to the dc case. The shape of the mobility spectrum reveals the presence of above THz hopping rates that are relevant for charge carrier transport. Differences in the mobilities in the polymer and the corresponding monomer material are caused by stronger energetic disorder of the monomer material.
Permanent Link: http://hdl.handle.net/11104/0212866