Lecture

Polarons and Bipolarons in Conjugated Polymers

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In course

MSE-486: Organic electronic materials

This course will introduce students to the field of organic electronic materials. The goal of this course is to discuss the origin of electronic properties in organic materials, charge transport mechanisms, chemical synthesis, materials processing, and dev ...

Description

This lecture covers the concept of polarons and bipolarons in conjugated polymers, discussing the energy differences between aromatic and quinoid states, exciton formation, chemical doping effects on conductivity, and the unique case of poly(aniline) showing conductivity without doping. It also explores the evidence of polarons and bipolarons through spectroscopic techniques, the formation of negative polarons and bipolarons, and the impact of structural dynamics, molecular rigidity, packing interactions, and static disorder on the effective conjugation length of charge carriers.

Instructor

Holger Frauenrath

Holger Frauenrath (born in Aachen, Germany) studied chemistry at RWTH Aachen , Germany from 1992 to 1997, with a focus on synthetic organic chemistry. He performed his PhD thesis from 1998 to 2001 in the research group of Prof Hartwig Höcker at RWTH Aachen, working on a project related to the stereospecific polymerization of methacrylates as well as their copolymerization with olefins using zirconocene catalysts. Holger Frauenrath then joined the group of Prof. Sam Stupp at Northwestern University , Evanston, IL, USA, as a postdoctoral fellow supported by a Feodor Lynen fellowship of the Alexander von Humboldt Foundation . His postdoctoral research projects were centered around the supramolecular self-assembly of rod-coil molecules. Holger Frauenrath returned to Germany in 2003 and started to build his own research group at FU Berlin, funded with an Emmy Noether Grant from the German Science Foundation . In 2005, the research group moved to the Department of Materials at ETH Zurich , Switzerland, where it became a scientifcally independent part of the Polymer Chemistry Group led by Prof. A. Dieter Schlüter . Holger Frauenrath obtained his Habilitation from ETH Zurich in 2009. In 2009, Holger Frauenrath has been appointed as a professor at the Institute of Materials (IMX) of the Ecole Polytechnique Federale de Lausanne (EPFL) , Switzerland, building the new Laboratory of Macromolecular and Organic Materials (LMOM) . In the same year, Holger Frauenrath was received the prestigious European Research Council (ERC) Starting Investigator grant.

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