This project focuses on understanding and improving the performance of conjugated polymers, a class of materials whose electronic conductivity makes them useful in a wide range of devices across energy generation and storage, biological and chemical sensors, and computation. The electronic performance of these materials is very sensitive to changes in how crystalline they are, and how organized the crystals are; however, there are currently only limited and general strategies to control this crystal organization. To develop new strategies for building this control, researchers at the University of Washington (UW) will produce a series of polymers with a highly controlled chemical structure that is specifically tuned to improve the crystal quality. These polymers will also help to build understanding of the connection between chemical structure and crystal quality, making it easier to predict and design better polymers in the future. Because of the importance of clean energy and interest in the community, this work will be broadly communicated in a number of different places. One major pathway will be through sharing the research lab’s work by demonstrating stretchable solar cells during visitations to classrooms, as well as participating in larger science events such as science and maker fairs, through the UW Materials Ambassadors program. The PI will also work with the UW College of Engineering Math Academy, working with underserved members of the community by providing opportunities for them to participate in research lab work before even graduating from high school.
Paracrystallinity in conjugated polymer backbones represents a critical limitation for conjugated polymer electronic conductivity, and current strategies to improve this parameter are currently extremely limited. To address this, researchers at the University of Washington seek to develop a new polymer backbone architecture, using an alternating pattern of polar and nonpolar side chains to improve polymer backbone paracrystallinity. Specifically, this work proposes to use the self-segregation of polar and nonpolar side chains to produce a polymer with high side-chain crystallinity. This polymer will then be processed using a variety of solvent and thermal processing conditions, to control the extent of side chain crystallinity. The effect on backbone paracrystallinity will be measured and correlated with the processing conditions and side-chain crystallinity. This correlation will build understanding of the interconnection between crystallizable side chains and the backbone paracrystallinity, and offer insight into the strategy of using side chain organization as a tool for improving the backbone paracrystallinity. The work will begin with polythiophene backbones but will be expanded to include fused rings and donor-acceptor copolymers. By delving into not just the side-chain self-segregation, but also the connection between processing conditions, side-chain crystallinity, and paracrystallinity, this research will provide a strategy to improving the performance of conjugated polymers. .
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
