A computational exploration of the crystal energy and charge-carrier mobility landscapes of the chiral [6]helicene molecule
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Accepted version
Author(s)
Type
Journal Article
Abstract
The potential of a given π-conjugated organic molecule in an organic semiconductor device is highly dependent on molecular packing, as it strongly influences the charge-carrier mobility of the material. Such solid-state packing is sensitive to subtle differences in their intermolecular interactions and is challenging to predict. Chirality of the organic molecule adds an additional element of complexity to intuitive packing prediction. Here we use crystal structure prediction to explore the lattice-energy landscape of a potential chiral organic semiconductor, [6]helicene. We reproduce the experimentally observed enantiopure crystal structure and explain the absence of an experimentally observed racemate structure. By exploring how the hole and electron-mobility varies across the energy–structure–function landscape for [6]helicene, we find that an energetically favourable and frequently occurring packing motif is particularly promising for electron-mobility, with a highest calculated mobility of 2.9 cm2 V−1 s−1 (assuming a reorganization energy of 0.46 eV). We also calculate relatively high hole-mobility in some structures, with a highest calculated mobility of 2.0 cm2 V−1 s−1 found for chains of helicenes packed in a herringbone fashion. Neither the energetically favourable nor high charge-carrier mobility packing motifs are intuitively obvious, and this demonstrates the utility of our approach to computationally explore the energy–structure–function landscape for organic semiconductors. Our work demonstrates a route for the use of computational simulations to aid in the design of new molecules for organic electronics, through the a priori prediction of their likely solid-state form and properties.
Date Issued
2018-01-05
Date Acceptance
2017-12-27
Citation
Nanoscale, 2018, 10, pp.1865-1876
ISSN
2040-3364
Publisher
Royal Society of Chemistry
Start Page
1865
End Page
1876
Journal / Book Title
Nanoscale
Volume
10
Copyright Statement
© The Royal Society of Chemistry 2018
Sponsor
Engineering & Physical Science Research Council (EPSRC)
The Royal Society
Engineering & Physical Science Research Council (EPSRC)
Engineering & Physical Science Research Council (EPSRC)
Engineering & Physical Science Research Council (EPSRC)
Commission of the European Communities
Grant Number
EP/L014580/1
UF120469
EP/M017257/1
EP/P000525/1
EP/P005543/1
742708
Subjects
10 Technology
02 Physical Sciences
03 Chemical Sciences
Nanoscience & Nanotechnology
Publication Status
Published
Date Publish Online
2018-01-05