Affiliation:
1. Lomonosov Moscow State University
2. Lomonosov Moscow State University; 3Enikolopov Institute of Synthetic Polymeric Materials Russian Academy of Sciences
Abstract
Organic light-emitting transistors are a new type of optoelectronic devices that combine the functionality of
OLED and a transistor that controls it. The working layer of these devices requires organic semiconductors
that combine high charge mobility with a high photoluminescence quantum yield. One of the promising classes
of such materials are thiophene-phenylene co-oligomers, the properties of which can be tuned over a wide range by adding various substituents. In this work, we address the effect of fluorination on the properties of
two model thiophene-phenylene co-oligomers with an annulated central fragment, P–TTA–P and P–BTBT–P.
It is shown that fluorination of both molecules lowers their frontier orbitals energy levels, and this should
enable electron transport in their crystals and films. At the same time, fluorination has a qualitatively different
effect on the delocalization of frontier orbitals, the width of the optical gap, the oscillator strength, the exciton
binding energy, and the Raman spectrum, which is explained by the difference in the equilibrium geometry
of fluorinated molecules. It is expected that the revealed relationships between the structure and properties
of the studied compounds will contribute to the rational design of organic semiconductors for efficient light
emitting devices.
Subject
Space and Planetary Science,General Physics and Astronomy,Astronomy and Astrophysics