Synthesis, characterization, and processing of new electroactive and photoactive polyesters derived from oligothiophenes

Synthesis of various polyesters involving oligothiophene (2-5) units has led to materials exhibiting a good processability together with tunable absorption (from 342 to 428 nm) and fluorescence (from 411 to 558 nm) properties. It has been also found that polyesters with quaterthiophene or pentathiophene units show some electroactivity affording the formation of radical cations and dimerized radical cations, while pentathiophene units even permit the formation of negative charge carriers. The presence of these charge carriers increases dramatically the conductivity to values up to 0.4 S/cm in both oxidized and reduced states. This good electrical transport of both p-type and n-type charge carriers combined with luminescent properties and Langmuir-Blodgett processability could lead to well-organized and efficient light-emitting devices.