Theoretical Investigation of Optoelectronic Properties of Aryl Substituted Pentacene Derivatives

Pentacene derivatives have recently emerged as a potential material for organic electronics such as OLEDs, OFETs, and OPVs. In this paper, we report a thorough investigation of a series of pentacene derivatives substituted at the 6,13 position with aryl groups, using density functional theory (DFT) and Marcus formalism. Dispersion corrected Austin-Frisch-Petersson (APFD) functional is used to explore the electronic, optical and charge transport properties. The computed energy gap between the HOMO and LUMO levels of the compounds lie in the visible range between 2.54 eV to 2.80 eV. The viability of these materials as a transport layer in OLED is evaluated by assessing their charge transport characteristics. The large transfer integral and low reorganization energy for electron transport are indicative of a reasonably high electron transfer rate. We find that the 6,13-dithien-2-yl pentacene show higher electron transfer rate and may act as an electron transport material. The substitution with 6,13-bis(5-methoxythien-2-yl) in the pentacene backbone causes a red shift of the optical absorption spectrum. Our results suggest that aryl substitution tunes the charge transport properties along with optical absorption energies of pentacene derivatives.