Effective temperature for hopping transport in a Gaussian DOS

TL;DR

This paper introduces the concept of an effective temperature to describe hopping transport in disordered materials with a Gaussian density of states, accounting for electric field effects on mobility.

Contribution

It demonstrates that both energy distribution and mobility can be characterized by a single effective temperature parameter, independent of charge carrier concentration.

Findings

Effective temperature depends on electric field magnitude.

Mobility varies with charge carrier concentration.

Applicable to systems with and without energy correlations.

Abstract

For hopping transport in disordered materials, the mobility of charge carriers is strongly dependent on temperature and the electric field. Our numerical study shows that both the energy distribution and the mobility of charge carriers in systems with a Gaussian density of states, such as organic disordered semiconductors, can be described by a single parameter - effective temperature, dependent on the magnitude of the electric field. Furthermore, this effective temperature does not depend on the concentration of charge carriers, while the mobility does depend on the charge carrier concentration. The concept of the effective temperature is shown to be valid for systems with and without space-energy correlations in the distribution of localized states.