Measurement of molecular motion in organic semiconductors by thermal diffuse electron scattering.


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Authors
Eggeman, Alexander S 
Illig, Steffen 
Troisi, Alessandro 
Sirringhaus, Henning  ORCID logo  https://orcid.org/0000-0001-9827-6061
Midgley, Paul A 
Abstract

Many of the remarkable electrical and optical properties of organic semiconductors are governed by the interaction of electronic excitations with intra- and intermolecular vibrational modes. However, in specific systems this interaction is not understood in detail at a molecular level and this has been due, at least in part, to the lack of easy-to-use and widely available experimental probes of the structural dynamics. Here we demonstrate that thermal diffuse scattering in electron diffraction patterns from organic semiconductors, such as 6,13-bistriisopropyl-silylethynyl pentacene, allows the dominant lattice vibrational modes to be probed directly. The amplitude and direction of the dominant molecular motions were determined by comparison of the diffuse scattering with simulations and molecular dynamics calculations. Our widely applicable approach enables a much deeper understanding of the structural dynamics in a broad range of organic semiconductors.

Description
Keywords
Electron Crystallography, phonons
Journal Title
Nat Mater
Conference Name
Journal ISSN
1476-1122
1476-4660
Volume Title
Publisher
Springer Science and Business Media LLC
Sponsorship
Engineering and Physical Sciences Research Council (EP/G060738/1)
Engineering and Physical Sciences Research Council (EP/H017712/1)
European Research Council (291522)
European Commission (312483)
Two of the authors, AE and PM, acknowledge financial support through EPSRC grant EP/H017712 and from the European Research Council under the European Union’s Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement 291522-3DIMAGE and the Seventh Framework Programme of the European Commission: ESTEEM2, contract number 312483, HS ackowledges the EPSRC for financial support through EP/G060738/1 and AT acknowledges the Leverhulme trust for support.