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Lecture

Polaronic Transport: Criteria and Mechanisms

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.

Electron mobility

In solid-state physics, the electron mobility characterises how quickly an electron can move through a metal or semiconductor when pulled by an electric field. There is an analogous quantity for holes, called hole mobility. The term carrier mobility refers in general to both electron and hole mobility. Electron and hole mobility are special cases of electrical mobility of charged particles in a fluid under an applied electric field. When an electric field E is applied across a piece of material, the electrons respond by moving with an average velocity called the drift velocity, .

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.

Polariton

In physics, polaritons pəˈlærᵻtɒnz,_poʊ- are quasiparticles resulting from strong coupling of electromagnetic waves with an electric or magnetic dipole-carrying excitation. They are an expression of the common quantum phenomenon known as level repulsion, also known as the avoided crossing principle. Polaritons describe the crossing of the dispersion of light with any interacting resonance. To this extent polaritons can also be thought of as the new normal modes of a given material or structure arising from the strong coupling of the bare modes, which are the photon and the dipolar oscillation.

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.

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Crystal Structures: Miller Indices and Atom Arrangement

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Electron Diffraction: Basics and Applications

Covers the fundamentals of electron diffraction and its applications in understanding crystal structures and symmetry, including lattice vectors, lattice planes, and dark-field imaging techniques.

Charge Formation and Delocalization: Solitons, Polarons, and Interfaces