Date: Tuesday, May 27, 2014
Time: 11:00 am
Speaker: Jason D. Azoulay, University of Southern Mississippi
Title: Narrow Band Gap Conjugated Polymers for Emergent Electronic Technologies
Location: 67-3111 Chemla Room
Research in the field of organic semiconducting materials has allowed for the development of commercially relevant technologies such as organic thin-film transistors (OTFTs), light-emitting diodes (OLEDs), photovoltaics (OPVs), sensors, molecular electronics and biocompatible medical materials. Research efforts in industry and academia remain unabated in areas where energy (in the form of light, electricity or heat) meet a wide variety of molecular and even biological systems. Despite significant research efforts there exists no strategy to modulate the properties of these materials precisely and the lack of understanding of the features that govern performance in these systems precludes their broad utilization. Through the development of a modular synthetic approach we demonstrate the capability to systematically influence the electron density along the main chain, aromatic stabilization of the constituent copolymer segments, the relative co-planarity of the conjugated backbone and degree of intermolecular coupling in the solid-state. These features directly influence the optoelectronic and physicochemical characteristics of the resultant materials, nature and properties of transient species, inter- and intramolecular charge transfer properties of holes and electrons and corresponding device performance parameters. The utility of these materials towards developing a better understanding of pertinent loss processes and understanding the nature of the transient species in light harvesting applications will be discussed. Furthermore, the extension of molecular conjugation via cross-conjugated structural motifs has afforded control over the frontier orbital energetics (separation, position, and alignment) that can be utilized to extend this functionality into the infrared spectral regions. Our findings bear implications necessary to explore and utilize new concepts in polymer electronics, photonics, and endow functionality relevant in emergent technologies.