DFT studies of perylenetetracarboxylic dianhydride and perylene diimide derivatives

Perylenetetracarboxylic dianhydride (PTCDA) and perylene diimide (PDI) have been widely used as photosensitizers in many applications. Photophysical properties are key factors for efficient application of these materials. Furthermore, many functionalization of these materials come from the motivation of tuning their solubility, which may affect the photophysical properties of the resulting materials. As such, it is imperative to study the electronic and photophysical properties of PTCDA and PDI derivatives. In this work, we report DFT studies of 36 molecules consisting 18 PTCDA molecules and 18 PDI derivatives with the same set of functionalization at the bay positions. DFT results show that the impact of functionalization is similar in HOMO and LUMO energies to both PTCDA and PDI derivatives. Analysis of electronic results indicates extension of electron delocalization along the bay positions 1 and 7 is important in altering absorption wavelengths or HOMO-LUMO gaps