Dependence of Regioregular Poly(3-hexylthiophene) Film Morphology and Field-Effect Mobility on Molecular Weight
Year: 2005
Type: article
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 π-stacking peak increases when the mobility increases for a constant MW. When the MW is changed, this correlation breaks down, confirming that in-plane π-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.
Source: Macromolecules
DOI: 10.1021/ma047415f
Authors: R. Joseph Kline, Michael D. McGehee, Ekaterina N. Kadnikova, Jinsong Liu, Jean M. J. Fréchet, Michael F. Toney
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
Awards: G1286251239, G1398330795, G1643223109, G2371548206, G262532246, G301008592, G303061748, G3192341023, G3444594369, G3520789527, G3715425138, G3799934621, G4235786860, G4654690619, Renewal Proposal for the National Nanofabrication Users Network, G5570207115, G6550344761, G7283024673, Center on Polymer Interfaces and Macromolecular Assemblies (CPIMA), G8099852790, G911061179, G969889393
OpenAlex ID: W2116650273