High-Performance Organic Electronic Materials by Contorting Perylene Diimides.

Abstract

Perylene diimide (PDI) is a workhorse of the organic electronics community. However, the vast majority of designs that include PDI substitute the core with various functional groups to encourage intimate cofacial contacts between largely planar PDIs. Over the past several years, we have observed the counterintuitive result that contorting the planar aromatic core of PDI leads to higher performing photovoltaics, photodetectors, batteries, and other organic electronic devices. In this Perspective, we describe how different modes of contortion can be reliably installed into PDI-based molecules, oligomers, and polymers. We also describe how these different contortions modify the observed optical and electronic properties of PDI. For instance, contorting PDIs into bowls leads to high-efficiency singlet fission materials, while contorting PDIs into helicene-like structures leads to nonlinear amplification of Cotton effects, culminating in the highest g-factors so far observed for organic compounds. Finally, we show how these unique optoelectronic properties give rise to higher performance organic electronic devices. We specifically note how the three-dimensional structure of these contorted aromatic molecules is responsible for the enhancements in performance we observe. Throughout this Perspective, we highlight opportunities for continued study in this rapidly developing organic materials frontier.