Charge carrier induced barrier height reduction at organic heterojunctions

TL;DR

This paper presents a theoretical model showing that charge accumulation at organic heterojunctions reduces the barrier height, significantly improving the accuracy of J-V characteristic predictions across various conditions.

Contribution

It introduces a charge carrier accumulation model that accounts for barrier height reduction, enhancing the understanding of charge transport in organic heterojunctions.

Findings

Charge accumulation reduces barrier height at heterojunctions.

Modified injection model accurately predicts experimental J-V data.

Model works across different electric fields and temperatures.

Abstract

In order to provide an accurate theoretical description of current density voltage (J-V) characteristics of an organic heterojunction device over a wide range of electric fields at various temperatures, it is proposed that an accumulation of charge carriers at the heterojunction will lead to a reduction in the barrier height across the heterojunction. Two well-known hole transporting materials, 4,4,4-Tris(N-3-methylphenyl-N-phenyl-amino) triphenylamine (MTDATA) and N,N-diphenyl-N,N-bis(1-naphthyl)(1,1-biphenyl)-4,4diamine (NPB) were used to fabricate unipolar heterojunction devices. It is found that the J-V characteristics depends strongly on applied bias. The simulated J-V characteristics of the heterojunction device, with the modified injection model, are found to be in excellent agreement with the experimental data.