Affiliation:
1. Lomonosov Moscow State University
Abstract
For efficient operation of many organic electronic devices, organic semiconductors with high charge carrier
mobility are required. However, in most of the known organic semiconductors, the charge mobility is low,
since it is limited by the strong local electron-phonon interaction. In the present work, using the example of
thiophene-phenylene co-oligomers, a class of organic semiconductors that combine a sufficiently high charge
mobility with light emission and therefore promising for light-emitting transistors and electrically pumped
lasers, the mechanism of suppression of the electron-phonon interaction by introducing electronegative atoms
or an additional thiophene ring is studied. It was found that such structural changes alter the contribution
of various vibrational modes to the local electron-phonon interaction, in particular, to the suppression of
the contribution of the low-frequency torsion mode. In addition, it is shown that for the two modes that
make the largest contribution to the local electron-phonon interaction in an unsubstituted oligomer, this
change correlates with their intensity of Raman scattering, and this confirms the promise of studying the
electron-phonon interaction using Raman spectroscopy. The results obtained improve the understanding
of the relationship between the local electron-phonon interaction and the molecular structure of organic
semiconductors, which is extremely important for the directed design of such materials with high charge
mobility.
Funder
Russian Science Foundation
Subject
Space and Planetary Science,General Physics and Astronomy,Astronomy and Astrophysics