Spectroscopic assessment of charge mobility in organic semiconductors

TL;DR

This paper introduces a spectroscopic method using low-frequency Raman spectra to assess charge mobility in organic semiconductors, addressing key challenges in understanding and quantifying charge transport for improved material development.

Contribution

The study presents a novel spectroscopic approach to evaluate dynamic disorder and charge mobility in organic semiconductors, linking spectral data with device performance.

Findings

Spectroscopic mobility correlates with device charge mobility.

Low-frequency Raman spectra reveal dynamic disorder affecting charge transport.

Method enables targeted search for high-mobility organic materials.

Abstract

Rapid progress in organic electronics demands new highly efficient organic semiconducting materials. Nevertheless, only few materials have been created so far that show reliable band-like transport with high charge mobilities, which reflects the two main obstacles in the field: the poor understanding of charge transport in organic semiconductors (OSs) and the difficulty of its quantification in devices. Here, we present a spectroscopic method for assessment of the charge transport in organic semiconductors. We show that the intensities of the low-frequency Raman spectrum allow calculation of the dynamic disorder that limits the charge carrier mobility. The spectroscopically evaluated mobility clearly correlates with the device charge mobility reported for various OSs. The proposed spectroscopic method can serve as a powerful tool for a focused search of new materials and highlights the disorder bottleneck in the intrinsic charge transport in high-mobility organic semiconductors.