High-Throughput Pressure-Dependent Density Functional Theory Investigation of Herringbone Polycyclic Aromatic Hydrocarbons: Part 2. Pressure-Dependent Electronic Properties

Abstract

Understanding the effect intermolecular interactions have on the electronic properties of highly conjugated/aromatic organic networks is important for optimizing these materials for optoelectronic device applications. Here, dispersion inclusive density functional theory (DFT + vdW) is used to study the effect of pressure up to 20 GPa on the intermolecular interactions of 40 herringbone polycyclic aromatic hydrocarbons. In the first part of this two-part study (10.1021/acs.jpcc.8b07209), we reported the pressure-induced structural changes. Here, we elucidate the relation between those structural changes and the electronic properties, where it is shown that increased pressure leads to variations in the intermolecular interactions and molecular conformations, resulting in alterations of the band dispersion, band gap (magnitude as well as direct/indirect), and semiconductor polarity (n-type vs p-type). Specifically, increased pressure increases the C–H···π and π···π interactions, typically leading to increase...