Chasing the "killer" phonon mode for the rational design of low disorder, high mobility molecular semiconductors

Schweicher, Guillaume and D'Avino, Gabriele and Ruggiero, Michael T. and Harkin, David J. and Broch, Katharina and Venkateshvaran, Deepak and Liu, Guoming and Richard, Audrey and Ruzié, Christian and Armstrong, Jeff and Kennedy, Alan R. and Shankland, Kenneth and Takimiya, Kazuo and Geerts, Yves H. and Zeitler, J. Axel and Fratini, Simone and Sirringhaus, Henning (2019) Chasing the "killer" phonon mode for the rational design of low disorder, high mobility molecular semiconductors. Advanced Materials, 31 (43). 1902407. ISSN 1521-4095 (https://doi.org/10.1002/adma.201902407)

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Abstract

Molecular vibrations play a critical role in the charge transport properties of weakly van der Waals bonded organic semiconductors. To understand which specific phonon modes contribute most strongly to the electron – phonon coupling and ensuing thermal energetic disorder in some of the most widely studied high mobility molecular semiconductors, we have combined state-of-the-art quantum mechanical simulations of the vibrational modes and the ensuing electron phonon coupling constants with experimental measurements of the lowfrequency vibrations using inelastic neutron scattering and terahertz time-domain spectroscopy. In this way we have been able to identify the long-axis sliding motion as a 'killer' phonon mode, which in some molecules contributes more than 80% to the total thermal disorder. Based on this insight, we propose a way to rationalize mobility trends between different materials and derive important molecular design guidelines for new high mobility molecular semiconductors.

  • Item type:Article
    ID code:69058
    Dates:
    Date
    Event
    25 October 2019
    Published
    12 September 2019
    Published Online
    25 July 2019
    Accepted
    Subjects:Science > Chemistry
    Department:Faculty of Science > Pure and Applied Chemistry
    Depositing user: Pure Administrator
    Date deposited:26 Jul 2019 09:51
    Last modified:21 Apr 2024 15:04
    URI:https://strathprints.strath.ac.uk/id/eprint/69058
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