Negative field‐dependent charge mobility in crystalline organic semiconductors with delocalized transportAndrey Kadashchuk
, Egon Pavlica
, Gvido Bratina
, Fei Tong
, 2018, izvirni znanstveni članek
Opis: Charge-carrier mobility has been investigated by time-of-flight (TOF) transient photocurrent in a lateral transport con- figuration in highly crystalline thin films of 2,7-dioctylbenzothieno [3,2-b] 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 ≥ 295 K. Moreover, the mobility was surprisingly found to decrease with electric field in the high-temperature region. These observations are not compat- ible 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.
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Povzetek najdenega: ...time of flight, organic semiconductors, single crystals...
Ključne besede: time of flight, organic semiconductors, single crystals
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