Sequence-Specific Placement of Defects in Pi-Conjugated Semiconducting Polymers

University Of Washington, Seattle WA

Investigators

Abstract

NON-TECHNICAL SUMMARY: The materials class, "pi-conjugated semiconducting polymers", that are being studied in this proposal are electronic polymers that have the potential to address needs ranging from energy usage, harvesting, and storage. Specifically, the polymers have applications in organic light emitting diodes (OLEDs), organic photovoltaics (OPVs), bioelectronics, sensors, and electronic skin. However, for these polymers to be used in a wide range of electronic applications, it is important to understand how the long polymer molecular chains fold in the solid state of the material and how this folding affects its electronic properties. To this end, the PI and her group at the University of Washington will develop, synthesize, and study a new class of pi-conjugated semiconducting polymers that can fold at specific locations along a polymer chain, and establish new ways to affect the optoelectronic properties of these polymers. The relevance of the project to a number of applications provides us with an opportunity to communicate the importance of science and engineering to the community. Specifically, an exhibition about polymers will be created in collaboration with the Pacific Science Center (a science museum in Seattle). Additionally, the PI will work with a group known as Diversity in Clean Energy (DICE) at the University of Washington to support women and underrepresented minorities in STEM fields. TECHNICAL SUMMARY: Within the field of pi-conjugated semiconducting polymers, there is a growing realization that defects such as homocoupling and end-groups can adversely affect the properties and thus the performance of these polymers in actual applications. However, what is not clearly understood is why these defects affect the properties in the way that they do. In this proposal, the PI and her group aim to shed light on how point defects can affect microstructure and thus their properties. The research entails the following: (i) synthesizing pi-conjugated semiconducting homopolymers with precisely spaced defects; (ii) assessing how the size of and spacing between defects affect the microstructure of the homopolymers; and (iii) expanding the design rules established in parts (i) and (ii) to alternating copolymers. The research is envisioned to provide means to design the microstructure of pi-conjugated semiconducting polymers with an unprecedented level of control instead of relying only on optimization methods as is typically done.