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Title: The Dependence of Regioregular Poly(3-Hexylthiophene) Film Morphology and Field-Effect Mobility on Molecular Weight

Abstract

Morphological characterization has been used to explain the previously observed strong correlation between charge carrier mobility measured with thin-film transistors and the number-average molecular weight (MW) of the conjugated polymer regioregular poly(3-hexylthiophene). Atomic force microscopy and x-ray diffraction show that the low mobility, low MW films have a highly ordered structure composed of nanorods and the high mobility, high MW films have a less ordered, isotropic nodule structure. Modifying the morphology for a constant MW by changing the casting conditions or annealing the samples strongly affects the charge transport and morphology in the low mobility, low MW films, but has little effect on the high MW films. In-plane grazing incidence x-ray scattering shows the in-plane {pi}-stacking peak increases when the mobility increases for a constant MW. When the MW is changed, this correlation breaks down, confirming that in-plane {pi}-stacking does not cause the mobility-MW relationship. We believe a combination of disordered domain boundaries and inherent effects of chain length on the electronic structure cause the mobility-MW relationship.

Authors:
Publication Date:
Research Org.:
Stanford Linear Accelerator Center (SLAC), Menlo Park, CA
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
839719
Report Number(s):
SLAC-PUB-10918
TRN: US200516%%664
DOE Contract Number:  
AC02-76SF00515
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANNEALING; ATOMIC FORCE MICROSCOPY; CASTING; CHAINS; CHARGE CARRIERS; CHARGE TRANSPORT; ELECTRONIC STRUCTURE; MOLECULAR WEIGHT; MORPHOLOGY; POLYMERS; SCATTERING; TRANSISTORS; X-RAY DIFFRACTION

Citation Formats

Kline, R. The Dependence of Regioregular Poly(3-Hexylthiophene) Film Morphology and Field-Effect Mobility on Molecular Weight. United States: N. p., 2004. Web. doi:10.2172/839719.
Kline, R. The Dependence of Regioregular Poly(3-Hexylthiophene) Film Morphology and Field-Effect Mobility on Molecular Weight. United States. https://doi.org/10.2172/839719
Kline, R. Fri . "The Dependence of Regioregular Poly(3-Hexylthiophene) Film Morphology and Field-Effect Mobility on Molecular Weight". United States. https://doi.org/10.2172/839719. https://www.osti.gov/servlets/purl/839719.
@article{osti_839719,
title = {The Dependence of Regioregular Poly(3-Hexylthiophene) Film Morphology and Field-Effect Mobility on Molecular Weight},
author = {Kline, R},
abstractNote = {Morphological characterization has been used to explain the previously observed strong correlation between charge carrier mobility measured with thin-film transistors and the number-average molecular weight (MW) of the conjugated polymer regioregular poly(3-hexylthiophene). Atomic force microscopy and x-ray diffraction show that the low mobility, low MW films have a highly ordered structure composed of nanorods and the high mobility, high MW films have a less ordered, isotropic nodule structure. Modifying the morphology for a constant MW by changing the casting conditions or annealing the samples strongly affects the charge transport and morphology in the low mobility, low MW films, but has little effect on the high MW films. In-plane grazing incidence x-ray scattering shows the in-plane {pi}-stacking peak increases when the mobility increases for a constant MW. When the MW is changed, this correlation breaks down, confirming that in-plane {pi}-stacking does not cause the mobility-MW relationship. We believe a combination of disordered domain boundaries and inherent effects of chain length on the electronic structure cause the mobility-MW relationship.},
doi = {10.2172/839719},
url = {https://www.osti.gov/biblio/839719}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2004},
month = {12}
}