Toward a better understanding of the doping mechanism involved in Mo(tfd-COCF$_3)_3$ doped PBDTTT-c

TL;DR

This paper investigates the doping mechanism in Mo(tfd-COCF3)3-doped PBDTTT-c, analyzing how doping efficiency varies with dopant concentration using optical and electrical methods to understand the limits of organic semiconductor doping.

Contribution

It provides a detailed analysis of doping mechanisms in PBDTTT-c, comparing charge transfer models and their impact on doping efficiency at high dopant levels.

Findings

Doping efficiency limits are linked to the doping mechanism.

Charge transfer complex (CTC) plays a significant role at high dopant concentrations.

The validity of the charge transfer model influences doping performance.

Abstract

In this study, we aim to improve our understanding of the doping mechanism involved in the polymer PBDTTT-c doped with(Mo(tfd-COCF3)3. We follow the evolution of the hole density with dopant concentration to highlight the limits of organic semiconductor doping. To enable the use of doping to enhance the performance of organic electronic devices, doping efficiency must be understood and improved. We report here a study using complementary optical and electrical characterization techniques, which sheds some light on the origin of this limited doping efficiency at high dopant concentration. Two doping mechanisms are considered, the direct charge transfer (DCT) and the charge transfer complex (CTC). We discuss the validity of the model involved as well as its impact on the doping efficiency.