Direct probe of the nuclear modes limiting charge mobility in molecular semiconductors

Thomas F. Harrelson, Varuni Dantanarayana, Xiaoyu Xie, Correy Koshnick, Dingqi Nai, Ryan Fair, Sean A. Nuñez, Alan K. Thomas, Tucker L. Murrey, Michael A. Hickner, John K. Grey, John E. Anthony, Enrique D. Gomez, Alessandro Troisi, Roland Faller, Adam J. Moulé

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

Recent theories suggest that low frequency dynamic intramolecular and intermolecular motions in organic semiconductors (OSCs) are critical to determining the hole mobility. So far, however, it has not been possible to probe these motions directly experimentally and therefore no unequivocal and quantitative link exists between molecular-scale thermal disorder and macroscale hole mobility in OSCs. Here we use inelastic neutron scattering to probe thermal disorder directly by measuring the phonon spectrum in six different small molecule OSCs, which we accurately reproduce with first principles simulations. We use the simulated phonons to generate a set of electron-phonon coupling parameters. Using these parameters, the theoretical mobility is in excellent agreement with macroscopic measurements. Comparison of mobility between different materials reveals routes to improve mobility by engineering phonon and electron-phonon coupling.

Original languageEnglish (US)
Pages (from-to)182-191
Number of pages10
JournalMaterials Horizons
Volume6
Issue number1
DOIs
StatePublished - Jan 2019

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Mechanics of Materials
  • Process Chemistry and Technology
  • Electrical and Electronic Engineering

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