Abstract
The greatest advantage of organic materials is the ability to synthetically tune desired properties. However, structural heterogeneity often obfuscates the relationship between chemical structure and functional properties. Inelastic neutron scattering (INS) is sensitive to both local structure and chemical environment and provides atomic level details that cannot be obtained through other spectroscopic or diffraction methods. INS data are composed of a density of vibrational states with no selection rules, which means that every structural configuration is equally weighted in the spectrum. This allows the INS spectrum to be quantitatively decomposed into different structural motifs. We present INS measurements of the semiconducting polymer P3HT doped with F4TCNQ supported by density functional theory calculations to identify two dominant families of undoped crystalline structures and one dominant doped structural motif, in spite of considerable heterogeneity. The differences between the undoped and doped structures indicate that P3HT side chains flatten upon doping.
Original language | English |
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Pages (from-to) | 2424-2435 |
Number of pages | 12 |
Journal | Macromolecules |
Volume | 50 |
Issue number | 6 |
DOIs | |
State | Published - Mar 28 2017 |
Funding
This research project was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under Award DE-SC0010419. This research was made possible by the use of the VISION beamline at ORNL's Spallation Neutron Source, which is supported by the Scientific User Facilities Division, Office of Basic Energy Sciences (BES), U.S. Department of Energy (DOE), under Contract DE-AC0500OR22725 with UT Battelle, LLC. Computational work was conducted on the Oak Ridge Leadership Computing Facility (OLCF) supported by the DOE. The computing resources were made available through the VirtuES (Virtual Experiments in Spectroscopy) project, funded by Laboratory Directed Research and Development program No. 7739).