Materials design based on theoretical characterization: Improving open-shell organic molecules for electronic applications

Abstract

In recent years, organic molecules with stable open-shell ground states have attracted growing interest due to their outstanding properties, i.e. responsive spin structures, high-spin ground states, two-photon absorption, or small band gap. Although a growing number of interesting materials has appeared, molecules often lack in thermal stability impeding their application in electronic devices. In this presentation, we will highlight routes but also dead ends in the quest for high-spin configurations in hydrocarbons. We benchmark a computational approach for the characterization of open-shell organic structures, which combines predictability with appropriate simulation resources. For polycyclic heteroaromatic hydrocarbons containing a benzoisoindole core, we explain why a supposedly open-shell material does not provide the desired characteristics [1]. On the contrary, we discuss the promising characteristics of stable polycyclic hydrocarbon diradicaloids as well as related tetraradicaloids [2,3,4]. We demonstrate that significant optimization of material properties can be achieved already by chemical functionalization, while the full potential of promising material groups like bisphenalenyl-based molecules is far from being fully exploited.