bei Google ScholarTitelangaben
Kadashchuk, Andrey ; Janneck, Robby ; Tong, Fei ; Fishchuk, Ivan I. ; Mityashin, Alexander ; Pavlica, Egon ; Köhler, Anna ; Heremans, Paul ; Rolin, Cedric ; Bratina, Gvido ; Genoe, Jan:
Negative field-dependent charge mobility in crystalline organic semiconductors with delocalized transport.
In: Chemical Papers.
Bd. 72
(2018)
Heft 7
.
- S. 1685-1695.
ISSN 1336-9075
DOI: https://doi.org/10.1007/s11696-018-0483-x
Abstract
Charge-carrier mobility has been investigated by time-of-flight (TOF) transient photocurrent in a lateral transport configuration in highly crystalline thin films of 2,7-dioctyl[1]benzothieno [3,2-b][1] benzothiophene (C8-BTBT) grown by a zone-casting alignment technique. High TOF mobility has been revealed that it is consistent with the delocalized nature of the charge transport in this material, yet it featured a positive temperature dependence at T≥295K. Moreover, the mobility was surprisingly found to decrease with electric field in the high-temperature region. These observations are not compatible with the conventional band-transport mechanism. We have elaborated an analytic model based on effective-medium approximation to rationalize the puzzling findings. The model considers the delocalized charge transport within the energy landscape formed by long-range transport band-edge variations in imperfect organic crystalline materials and accounts for the field-dependent effective dimensionality of charge transport percolative paths. The results of the model calculations are found to be in good agreement with experimental data.