Correlating anisotropic mobility and intermolecular phonons in organic semiconductors to investigate transient localization

Published: March 19, 2019

Author(s)

Emily G. Bittle, Adam J. Biacchi, Lisa A. Fredin, Andrew A. Herzing, Thomas C. Allison, Angela R. Hight Walker, David J. Gundlach

Abstract

Charge transport in organic semiconductors is governed by a mix of polaron hopping and band- like transport mechanisms. The energy of polaron hopping and formation are similar in magnitude to the energies of inter- and intra- molecular modes, which points to the important role that these modes have on charge transport. Intermolecular modes are theorized to result in a dynamic localization of charge carriers which limits electronic performance of the bulk material. Here, we introduce a novel framework to investigate the role that normal intermolecular modes have on charge transport in single crystal tetracene. We correlate mode energies and directionality from polarized Raman spectroscopy, transmission electron microscopy, and density functional theory with anisotropic transport measured on a field-effect transistor to define influential modes on important charge transport directions. Select modes are more likely to inhibit or promote charge transport along the high and low mobility axes, relating transient localization effects and anisotropic mobility.
Citation: Communications Physics
Volume: 2
Issue: 29
Pub Type: Journals

Keywords

organic semiconductor, anisotropic properties, Raman spectroscopy, Density functional theory, transistor
Created March 19, 2019, Updated March 19, 2019