Transient localization in crystalline organic semiconductors

TL;DR

This paper demonstrates how optical conductivity measurements can directly probe charge carrier dynamics and localization in doped crystalline organic semiconductors, revealing the impact of lattice disorder on transport properties.

Contribution

It introduces a method based on the Kubo formula to analyze optical conductivity data for extracting quantum dynamical quantities in disordered semiconductors.

Findings

Identification of electron localization due to lattice disorder

Breakdown of semiclassical transport in organic semiconductors

Quantification of scattering rates and localization length

Abstract

A relation derived from the Kubo formula shows that optical conductivity measurements below the gap frequency in doped semiconductors can be used to probe directly the time-dependent quantum dynamics of charge carriers. This allows to extract fundamental quantities such as the elastic and inelastic scattering rates, as well as the localization length in disordered systems. When applied to crystalline organic semiconductors, an incipient electron localization caused by large dynamical lattice disorder is unveiled, implying a breakdown of semiclassical transport.