Title:
Tunable Crystallinity in Poly(3-Hexylthiophene) and its Impact on Charge Transport
Tunable Crystallinity in Poly(3-Hexylthiophene) and its Impact on Charge Transport
Author(s)
Aiyar, Avishek R.
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Abstract
The properties of poly(alkylthiophenes) in solution are found to have a
profound impact on the self-assembly process and thus the microstructural
and electrical properties of the resultant thin films. Ordered
supramolecular precursors can be formed in regioregular poly(3-
hexylthiophene) (P3HT) solutions through the application of low intensity
ultrasound. These precursors survive the casting process, resulting in
a dramatic increase in the degree of crystallinity of the thin films
obtained by spin coating. The crystallinity of the films is tunable, with a
continuous evolution of mesoscale structures observed as a function of
ultrasonic irradiation time. The photophysical properties of P3HT in
solution as well in the solid state suggest that the application of
ultrasound leads to a π stacking induced molecular aggregation resulting
in field effect mobilities as high as 0.03 cm2V-1s-1. A multiphase
morphology, comprising short quasi-ordered and larger, ordered
nanofibrils embedded in a disordered amorphous phase is formed as a
result of irradiation for at least 1 minute. We identify two distinct regions
of charge transport characterized by an initial sharp increase in the field
effect mobility by two orders of magnitude due to an increase in crystallinity
up to the percolation limit, followed by a gradual saturation
where the mobility becomes independent of the thin film microstructure.
Sponsor
Dow Chemical Company
Date Issued
2011-10-05
Extent
26:21 minutes
Resource Type
Moving Image
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Resource Subtype
Lecture
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