Band dispersion and electronic lifetimes in crystalline organic semiconductors

TL;DR

This paper investigates the microscopic interactions affecting photoemission spectra in crystalline organic semiconductors, challenging existing theories of polaronic band narrowing and proposing an alternative explanation based on temperature and momentum dependence.

Contribution

It provides a theoretical analysis disentangling microscopic interactions in OSC and questions the validity of polaronic band narrowing as the main transport mechanism.

Findings

Polaronic thermal band narrowing is inconsistent with experimental parameters.

An alternative explanation for spectral trends is proposed.

Disentangling microscopic interactions via temperature and momentum dependence is effective.

Abstract

The consequences of several microscopic interactions on the photoemission spectra of crystalline organic semiconductors (OSC) are studied theoretically. It is argued that their relative roles can be disentangled by analyzing both their temperature and their momentum/energy dependence. Our analysis shows that the polaronic thermal band narrowing, that is the foundation of most theories of electrical transport in OSC, is inconsistent in the range of microscopic parameters appropriate for these materials. An alternative scenario is proposed to explain the experimental trends.