TY - JOUR
T1 - Chasing the "killer" phonon mode for the rational design of low disorder, high mobility molecular semiconductors
AU - Schweicher, Guillaume
AU - D'Avino, Gabriele
AU - Ruggiero, Michael T.
AU - Harkin, David J.
AU - Broch, Katharina
AU - Venkateshvaran, Deepak
AU - Liu, Guoming
AU - Richard, Audrey
AU - Ruzié, Christian
AU - Armstrong, Jeff
AU - Kennedy, Alan R.
AU - Shankland, Kenneth
AU - Takimiya, Kazuo
AU - Geerts, Yves H.
AU - Zeitler, J. Axel
AU - Fratini, Simone
AU - Sirringhaus, Henning
PY - 2019/10/25
Y1 - 2019/10/25
N2 - 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.
AB - 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.
KW - electron-photon coupling
KW - molecular vibrations
KW - organic semiconductors
U2 - 10.1002/adma.201902407
DO - 10.1002/adma.201902407
M3 - Article
SN - 1521-4095
VL - 31
JO - Advanced Materials
JF - Advanced Materials
IS - 43
M1 - 1902407
ER -