ИСТИНА

One of the most important factors limiting electrical mobility in organic semiconductors (OSC) is strong electron-phonon coupling, which makes charge transport very sensitive to inter- and intramolecular vibrations. Specifically, low-frequency vibrations were predicted to control coherent (band-like) charge transport in high mobility OSC [1,2]. In this work, we applied Raman spectroscopy to study the impact of electron-phonon coupling on charge transport in high mobility OCS. We derived a relation between Raman intensity and the contribution of vibrational modes to local and non-local electron-phonon coupling. As a result, we formulated a figure-of-merit (FOM) for the search of OSC with weak non-local electron-phonon coupling and hence having potentially high carrier mobility. We measured FOM for a series of high-mobility OSС and found that it clearly correlates with the charge intrinsic mobility. Moreover, the FOM temperature dependence also correlates with that of charge mobility. We anticipate that the proposed approach enables an easy and practical way for fast search of high mobility OSC prior their studies in electronic devices. The authors acknowledge funding from Russian Foundation for Basic Research (projects #16-32-60204 mol_a_dk, #17-02-00841). [1] I.Y. Chernyshov et al., J. Phys. Chem. Lett., 8 (2017) 2875-2880. [2] S. Illig et al., Nat. Commun., 7 (2016) 10.