(521f) Enhancing Charge Transport through Block Copolymer Architectures

Conjugated block copolymers provide an opportunity to control the active layer morphology of organic electronic devices. Previous work has demonstrated that photovoltaic devices with donor-acceptor block copolymers as the active layer outperform devices comprised of the constituent polymers. Self-assembly into lamellar morphologies leads to nanoscale domains on the scale of the exciton diffusion length while providing pathways for charge extraction. We have also recently explored linking a strongly crystalline block to a weakly crystalline polymer to intricately control local order. Promoting crystallization in one block can promote tight packing in the second block, potentially enhancing the electronic coupling between chains. Measurements of the charge transport characteristics of conjugated block copolymers reveals excellent charge mobilities for electron transport with aluminum source and drain contacts in a bottom gate, bottom contact transistor configuration. As a consequence of promoting close chain packing in the weakly crystalline block with the block copolymer architecture, we find that electron mobilities are higher for the block copolymer than for either of the homopolymers.