September 19, 2014 - 3:00pm - 4:00pm
We will address the synthesis and optimization of the morphology of solution processed π-conjugated oligomers and polymers, as they are applied in organic electronic devices. We seek to address the processing gap that is holding back developments in organic electronics, wherein laboratory experiments are most often carried out using spin-coating or drop-casting, yielding materials whose interfacial properties and morphologies are distinctly different from what is obtained using more practical roll-to-roll methods. We will discuss the control of morphology via a combination of structure and processing method (focusing on spray, blade and slot-die coating), and use organic photovoltaic (OPV) and electrochromic polymer (ECP) platforms for materials characterization. The flexible synthetic chemistry of dioxythiophene-based polymers has allowed us to complete the color palette of vibrantly colored to transmissive switching electrochromes of any color, including black. Using thiophene-based donors and linkers, we use a Donor-Acceptor (D-A) arrangement with isoindigo, thienoisoindigo, and diketopyrrolopyrrole (DPP) acceptors to prepare light harvesting molecules and polymers which serve as electron donor materials in bulk heterojunction OPV. We have demonstrated how the mixing of symmetric and asymmetric molecules provide compositions that form films with small crystalline features, elevated charge mobility, and enhanced PV properties.