Assessing the Role of Inter-Molecular Interactions in a Perylene-Based Nanowire Using First-Principles Many-Body Perturbation Theory

We present a first-principles many-body perturbation theory study of the role of inter-molecular coupling on the optoelectronic properties of a one-dimensional p-stacked nanowire composed of perylene-3,4,9,10-tetracarboxylic diimide (PTCDI) molecules on a DNA-like backbone. We determine that strong inter-molecular electronic coupling results in large bandwidths and low carrier effective masses, suggesting a high electron mobility material. Additionally, by including the role of finite temperature phonons on optical absorption via a newly presented approach, we predict that the optical absorption spectrum at room temperature is significantly altered from room temperature due to allowed indirect transitions, while the exciton delocalization and binding energy, a measure of inter-molecular electronic interactions, remains constant. Overall, our studies indicate that strong inter-molecular coupling can dominate the optoelectronic properties of π-conjugated 1D systems even at room temperature.