Lecture

Polaronic Transport: Criteria and Mechanisms

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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 polaronic transport, where charge carriers become localized due to dynamic disorder in an otherwise ordered crystal, leading to thermal activated inter-site hopping. The discussion includes the Holstein model for transfer rate, charge mobility regimes, and temperature dependence of charge transport.

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.

Official source

Related concepts (32)

Crystal structure

In crystallography, crystal structure is a description of the ordered arrangement of atoms, ions, or molecules in a crystalline material. Ordered structures occur from the intrinsic nature of the constituent particles to form symmetric patterns that repeat along the principal directions of three-dimensional space in matter. The smallest group of particles in the material that constitutes this repeating pattern is the unit cell of the structure.

Polaron

A polaron is a quasiparticle used in condensed matter physics to understand the interactions between electrons and atoms in a solid material. The polaron concept was proposed by Lev Landau in 1933 and Solomon Pekar in 1946 to describe an electron moving in a dielectric crystal where the atoms displace from their equilibrium positions to effectively screen the charge of an electron, known as a phonon cloud. This lowers the electron mobility and increases the electron's effective mass.

Crystal system

In crystallography, a crystal system is a set of point groups (a group of geometric symmetries with at least one fixed point). A lattice system is a set of Bravais lattices. Space groups are classified into crystal systems according to their point groups, and into lattice systems according to their Bravais lattices. Crystal systems that have space groups assigned to a common lattice system are combined into a crystal family. The seven crystal systems are triclinic, monoclinic, orthorhombic, tetragonal, trigonal, hexagonal, and cubic.

Cubic crystal system

In crystallography, the cubic (or isometric) crystal system is a crystal system where the unit cell is in the shape of a cube. This is one of the most common and simplest shapes found in crystals and minerals. There are three main varieties of these crystals: Primitive cubic (abbreviated cP and alternatively called simple cubic) Body-centered cubic (abbreviated cI or bcc) Face-centered cubic (abbreviated cF or fcc) Note: the term fcc is often used in synonym for the cubic close-packed or ccp structure occurring in metals.

Charge carrier

In physics, a charge carrier is a particle or quasiparticle that is free to move, carrying an electric charge, especially the particles that carry electric charges in electrical conductors. Examples are electrons, ions and holes. The term is used most commonly in solid state physics. In a conducting medium, an electric field can exert force on these free particles, causing a net motion of the particles through the medium; this is what constitutes an electric current.

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