Role of side-shain branching on thin-film structure and electronic properties of polythiophenes

Scott Himmelberger, Duc T. Duong, John E. Northrup, Jonathan Rivnay, Felix P V Koch, Bryan S. Beckingham, Natalie Stingelin, Rachel A. Segalman, Stefan C B Mannsfeld, Alberto Salleo

Research output: Contribution to journalArticlepeer-review

53 Scopus citations

Abstract

Side-chain engineering is increasingly being utilized as a technique to impact the structural order and enhance the electronic properties of semiconducting polymers. However, the correlations drawn between structural changes and the resulting charge transport properties are typically indirect and qualitative in nature. In the present work, a combination of grazing incidence X-ray diffraction and crystallographic refinement calculations is used to determine the precise molecular packing structure of two thiophene-based semiconducting polymers to study the impact of side-chain modifications. The optimized structures provide high-quality fits to the experimental data and demonstrate that in addition to a large difference in interchain spacing between the two materials, there exists a significant disparity in backbone orientation as well. The calculated structures are utilized in density functional theory calculations to determine the band structure of the two materials and are shown to exhibit a dramatic disparity in interchain dispersion which accounts for the large observed difference in charge carrier mobility. The techniques presented here are meant to be general and are therefore applicable to many other highly diffracting semicrystalline polymers.

Original languageEnglish (US)
Pages (from-to)2616-2624
Number of pages9
JournalAdvanced Functional Materials
Volume25
Issue number17
DOIs
StatePublished - May 6 2015

Keywords

  • X-ray diffraction
  • organic semiconductors
  • polymers
  • structures
  • thin films

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

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