Molecular Properties of Thiophene-Based Donor-Acceptor-Donor Small Molecules with Well-Defined Structures

Novel donor-acceptor-donor small molecules based on oligothiophenes with well-defined structures have been synthesized, and their thermal, optical, electrochemical, and electronic properties have been investigated. It was found that the introduction of alkoxy groups as side chains of the oligothiophene units increased the phase transition temperature, resulted in a red-shift in the absorption and emission spectra, and reduced the oxidation potentials compared with those of alkyl-substituted analogs. The origin of these changes is discussed from the perspective of the electronic structures of the compounds.