Synthesis and characterization of new chiral oligothiophenes for innovative optoelectronic applications

In recent years, ¶-conjugated polymers and oligomers have found considerable attention as organic semiconductor in the field of optoelectronics; in this field a very important role is played by oligothiophene-based systems. Their fundamental optical and electrical properties (light absorption and emission, charge transport, exciton transfer, etc.) depend not only on their chemical structure and confor-mation assumed, but also on the supramolecular interactions and nano/mesoscale organi-zation in the solid-state1. Chirality represents a way of controlling supramolecular aggre-gation of these systems: the introduction of chiral groups in their structure can drive them to organize into architectures with chiral geometries, where a perfect alignment between proximate chains is disfavoured with respect to a twisted arrangement. Moreover, non-racemic chiral ¶-conjugated systems can be studied using chiroptical spectroscopic tech-niques, in particular the electronic circular dichroism (ECD), which give access to a range of structural information otherwise not observable with other common spectroscopies. However, more importantly, these compounds may be used as chiral organic semi-conductors in novel optoelectronic applications: circularly polarized light sensors2, OFET able to discriminate enantiomers3, spin filters4, etc. In light of this, we designed and synthesized a set of new chiral oligothiophenes for the realization of some innovative optoelectronic devices.