Theory of the field-effect mobility in amorphous organic transistors

TL;DR

This paper develops a theoretical model for the field-effect mobility in amorphous organic transistors, successfully explaining experimental data for different materials and conditions.

Contribution

It introduces an analytic expression for mobility based on a percolation hopping model combined with transistor physics, advancing understanding of amorphous organic transistors.

Findings

The model accurately describes the gate-voltage dependence of mobility.

The theory matches temperature-dependent mobility measurements.

Good agreement with experiments on different organic materials.

Abstract

The field-effect mobility in an organic thin-film transistor is studied theoretically. From a percolation model of hopping between localized states and a transistor model an analytic expression for the field-effect mobility is obtained. The theory is applied to describe the experiments by Brown et al. [Synth. Met. 88, 37 (1997)] on solution-processed amorphous organic transistors, made from a polymer (polythienylene vinylene) and from a small molecule (pentacene). Good agreement is obtained, both with respect to the gate-voltage and the temperature dependence of the mobility.