Electronic properties of organic molecular semiconductors

Date

Oct 24, 2011

Time

11:45 AM - 12:45 PM

Speaker

Dr. Simone Fratini

Affiliation

Institut Néel-CNRS, Grenoble, France

Language

en

Main Topic

Materialien

Other Topics

Materialien, Physik

Host

Grit Rötzer

Description

The interaction of electrons with molecular vibrations and lattice deformations is known to play a fundamental role in organic semiconductors, and is often regarded as one of the primary causes of the moderate electronic mobilities realized in these materials. The fundamental mechanisms governing the charge dynamics are however poorly understood. The electronic mean-free path is typically comparable or shorter than the intermolecular spacing, which causes a breakdown of the band scenario and calls for new concepts that go beyond semiclassical Boltzmann transport. In this talk I will present some recent theoretical developments that shed some light on the dual nature ---partly itinerant, partly localized--- of the electronic excitations in organic semiconductors. Based on a generalization of the Kubo formula, I will show how the puzzling transport properties in these materials can be understood in terms of a "transient" localization phenomenon, whose direct experimental signature is visible in the measured optical conductivity. I shall conclude by analyzing how the photoemission spectra of organic semiconductors are modified by electron-vibration interactions.

Last modified: Oct 24, 2011, 9:35:07 AM