Chemistry Seminar Series

Wed, 31 Oct 2018
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Dr. Dwight Seferos

University of Toronto

Advances in Polymer Semiconductors and Energy Storage Devices

Wednesday, October 31, 2018
B9201 @ 3:30 p.m.

Host: Dr. Loren Kaake

Abstract

The Seferos group has been fascinated by how one can rationally design the properties of organic electronic materials. Some of their work has focused on the development of conjugated polymers that self-organize at the nanoscale by spontaneous phase-separation. The Seferos group has been interested in conjugated block copolymers where each block contains a distinct heterocycle. These polymers are fundamentally important for testing the limits of phase-separation as the polymers transform from the solvated state to the solid material phase. These polymers are also useful in optoelectronic devices where nanoscale structure is important. In this context, Seferos has developed selenophene-thiophene block copolymers and discovered that these copolymers undergo a significant amount of phase separation. This is surprising given the chemical similarity of the repeat units, however several properties, including crystal packing, differ in these polyheterocycles and that leads to rich phase behaviour. Seferos and group have also learned how to synthesize polymers and delocalized molecules based on tellurophene, and identified several unexpected properties in these materials including reversible binding of small molecules. These polymers have found utility as printed transistors and thermoelectric heat recovery devices. Finally, the Seferos group has developed redox active polymers and organic frameworks. The polymers are based on biologically derived redox moieties, making them sustainable materials that have capacities that make them well-suited for organic lithium ion batteries. The porous materials sequester ions into their channels and form robust and highly reversible electrodes. The synthesis, properties and applications of these materials will be discussed.

Keywords

Conjugated polymers; selenophene-thiophene block copolymers; phase-separation; polyheterocycles; tellurophene; printed transistors and thermoelectric heat recovery devices; biologically derived redox active polymers; organic lithium ion batteries