(750f) Understanding Self-Assembly of All-Conjugated Block Copolymers

Blends of conjugated polymers have significant potential for solution-processed optoelectronic applications such as organic photovoltaics (OPVs) and organic light-emitting diodes (OLEDs). Such blends can have broad absorbance spectra and significantly larger open circuit voltages compared with polymer-fullerene OPVs. However, a significant drawback of conjugated polymer blends is their tendency to phase separate. Here, we explore two methods for creating self-assembled mixtures of two or more conjugated polymers. In a first method, copper-catalyzed azide-alkyne “click” chemistry is used to synthesize all-conjugated block copolymers with a flexible linker. This versatile synthetic method gives access to all-conjugated block copolymers which self-assemble into nanoscale donor/acceptor structures. In a second approach, conjugated polymers are end-capped with a small molecule capable of forming hydrogen bonds. We show that conjugated polymers with hydrogen bonding end groups can form uniformly mixed polymer films. We will focus on the synthesis and structure of polymer films created using these two approaches and present data on OPVs based on these materials.