Chemical potential in disordered organic materials

TL;DR

This paper analytically derives the relationship between chemical potential and carrier concentration in disordered organic materials with Gaussian disorder, covering non-degenerate, degenerate, and saturated regimes, aiding understanding of charge mobility.

Contribution

It provides the first analytical expressions for chemical potential as a function of carrier concentration in different regimes of disordered organic materials.

Findings

Analytical formulas for chemical potential in non-degenerate, degenerate, and saturated regimes.

Dependence of chemical potential on energetic disorder and carrier concentration.

Enhanced understanding of charge mobility mechanisms in organic electronics.

Abstract

Charge carrier mobility in disordered organic materials is being actively studied, motivated by several applications such as organic light emitting diodes and organic field-effect transistors. It is known that the mobility in disordered organic materials depends on the chemical potential which in turn depends on the carrier concentration. However, the functional dependence of chemical potential on the carrier concentration is not known. In this study, we focus on the chemical potential in organic materials with Gaussian disorder. We identify three cases of non-degenerate, degenerate and saturated regimes. In each regime we calculate analytically the chemical potential as a function of the carrier concentration and the energetic disorder from the first principles.