Doping front instabilities in organic semiconductors: a means for optimizing optoelectronic devices

TL;DR

This paper develops a nonlinear theory of doping front instabilities in organic semiconductors, showing how these instabilities accelerate doping and can be controlled to optimize optoelectronic device performance.

Contribution

It introduces a nonlinear theoretical framework for doping front instabilities, aligning well with experimental data and guiding device optimization.

Findings

Instability accelerates doping process significantly.

Theoretical predictions match experimental measurements.

Control of front shape enables optimization of device performance.

Abstract

Recently, it was demonstrated that electrochemical doping fronts in organic semiconductors ex- hibit a new fundamental instability growing from multidimensional perturbations [Phys. Rev. Lett. 107, 016103 (2011)]. In the instability development, linear growth of tiny perturbations goes over into a nonlinear stage of strongly distorted doping fronts. Here we develop the nonlinear theory of the doping front instability and predict the key parameters of a distorted doping front, such as its velocity, in close agreement with the experimental data. We show that the instability makes the electrochemical doping process considerably faster. We obtain the self-similar properties of the front shape corresponding to the maximal propagation velocity, which allows for a wide range of controlling the doping process in the experiments. The theory developed provides the guide for optimizing the performance of organic optoelectronic devices.