Understanding Excited-States of a Perylene Diimide Nanowire from First Principles Theory

Perylene-3,4,9,10-tetracarboxylic diimide (PTCDI) are promising optoelectronic materials; they possess strong optical absorption and emission properties, along with a propensity for self-assembly and excellent stability. We utilize density functional theory and many-body perturbation theory within the GW/BSE approximation to investigate the optoelectronic properties of a periodic assembly of PTCDI DNA base surrogates. We predict a bandstructure with significant bandwidth (~0.8 eV) and several spatially delocalizated low-energy optically excited-states. By incorporating electron-phonon interactions, we determine that at finite temperature, the bandwidth is reduced and exciton binding increased, leading to localization of excited-states.