Invited Speaker：Prof. Dwight Seferos

Introduction：Dwight Seferos is Full Professor of Chemistry, Chemical Engineering, and Canada Research Chair in Polymer Nanomaterials at the University of Toronto. He completed a BSc in 2001 from Western Washington University, a Ph.D. in 2006 with Gui Bazan at UCSB, and was an American Cancer Society Postdoctoral Fellow with Chad Mirkin at Northwestern before beginning his independent career at the University of Toronto in 2009. Research in the Seferos group concerns the design, synthesis, characterization and device engineering of organometallic and organic materials, specifically those composed of selenophene and tellurophene. Seferos has authored or coauthored over 100 publications, holds numerous patents, and is the founder of the start-up Pliant Power Devices. He has been recognized with many national and international awards including the DuPont Young Professor Award, Alfred P. Sloan Research Fellowship, Canada Research Chair, and ACS Harry Gray Award for Creativity in Inorganic Chemistry.

【Title】Electronically Delocalized Molecules and Polymers that Contain Selenium and Tellurium

Time:  10:10-12:00 am, Dec.14th,2017

Location:  New MSE Building, No. 01 Meeting Room

Abstract：For over 8 years my students and I have been fascinated by how one can incorporate selenium and telluriumin top-delocalized molecules and polymers and how this in turn influences their properties. Much of our work has focused on the heterocycle tellurophene, which is the heaviest of the chalcogen heterocycles. Tellurophene chemistry had been virtually unknown, but through the course of our investigations we have learned how to synthesize p-delocalized molecules and polymers based on tellurophene. This has allowed us to identify several unexpected properties in these molecules including their ability to undergo facile halogen additional at the Te center and undergo subsequent halogen photo elimination with low energy light. This has lead us to conclude that these compounds are useful for photochemical halogen splitting and may be useful radical halogenation catalysts. Other work in my group has focused on the development of selenophene and tellurophene-based conjugated polymers. We have developed the controlled or ‘living’ synthesis of these challenging polyheterocycles and used this knowledge to develop polyheterocycles with complex architectures such as di- and tri-block copolymers and cyclic polymers. The block copolymers self-organize at the nanoscale by spontaneous phase-separation, which is largely driven by the differences in crystallinity within the blocks. When investigating the optoelectronic properties of these compounds, we find that they have a very narrow optical band-gap and a high charge-transport ability relative to the lighter heterocycle analogs. The polymers form the basis of the active semiconducting component in transistors and solar cells and often have high performance metrics. Finally, we have recently developed covalent frameworks based on selenophene and tellurophenes and discovered that their early oxidation potential makes them promising for energy storage applications. Selenophene and tellurophene chemistry, from synthesis to application, will be discussed.