title: Reducing dynamic disorder in small-molecule organic semiconductors by suppressing large-amplitude thermal motions.
abstract: Thermal vibrations and the dynamic disorder they create can detrimentally affect the transport properties of van der Waals bonded molecular semiconductors. The low-energy nature of these vibrations makes it difficult to access them experimentally, which is why we still lack clear molecular design rules to control and reduce dynamic disorder. In this study we discuss the promising organic semiconductors rubrene, 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothio-phene and 2,9-di-decyl-dinaphtho-[2,3-b:20,30-f]-thieno-[3,2-b]-thiophene in terms of an exceptionally low degree of dynamic disorder. In particular, we analyse diffuse scattering in transmission electron microscopy, to show that small molecules that have their side chains attached along the long axis of their conjugated core are better encapsulated in their crystal structure, which helps reduce large-amplitude thermal motions. Our work provides a general strategy for the design of new classes of very high mobility organic semiconductors with a low degree of dynamic disorder.
authors.affiliation: Optoelectronics Group, Cavendish Laboratory, University of Cambridge, JJ Thompson Avenue, Madingley Road, Cambridge CB3 0HE, UK.
authors.forename: Steffen
authors.initials: S
authors.lastname: Illig
authors.affiliation: Department of Materials Science and Metallurgy, University of Cambridge, Charles Babbage Road, Cambridge CB3 0FS, UK.
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Eggeman
authors.affiliation: Department of Chemistry and Centre for Scientific Computing, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Troisi
authors.affiliation: Optoelectronics Group, Cavendish Laboratory, University of Cambridge, JJ Thompson Avenue, Madingley Road, Cambridge CB3 0HE, UK.
authors.forename: Lang
authors.initials: L
authors.lastname: Jiang
authors.affiliation: Optoelectronics Group, Cavendish Laboratory, University of Cambridge, JJ Thompson Avenue, Madingley Road, Cambridge CB3 0HE, UK.
authors.forename: Chris
authors.initials: C
authors.lastname: Warwick
authors.affiliation: Optoelectronics Group, Cavendish Laboratory, University of Cambridge, JJ Thompson Avenue, Madingley Road, Cambridge CB3 0HE, UK.
authors.forename: Mark
authors.initials: M
authors.lastname: Nikolka
authors.affiliation: Optoelectronics Group, Cavendish Laboratory, University of Cambridge, JJ Thompson Avenue, Madingley Road, Cambridge CB3 0HE, UK.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Schweicher
authors.affiliation: School of Chemistry, University of Manchester, Oxford Road, Manchester M13 0PL, UK.
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Yeates
authors.affiliation: Faculté des Sciences, Université Libre de Bruxelles, Boulevard du Triomphe, Brussels 1050, Belgium.
authors.forename: Yves
authors.initials: Y
authors.lastname: Henri Geerts
authors.affiliation: Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-005, USA.
authors.forename: John E
authors.initials: JE
authors.lastname: Anthony
authors.affiliation: Optoelectronics Group, Cavendish Laboratory, University of Cambridge, JJ Thompson Avenue, Madingley Road, Cambridge CB3 0HE, UK.
authors.forename: Henning
authors.initials: H
authors.lastname: Sirringhaus