Theoretical Investigation of Perylene Diimide derivatives as Acceptors to Match with Benzodithiophene based Donors for Organic Photovoltaic Devices

Abstract

Abstract Optoelectronic properties of PDI derivatives (PDI-1–PDI-28) have been studied by inserting functional groups (–CN, –NO2 and –SO2) at different positions, by using DFT and TD-DFT functional at CAM-B3LYP/6-31 (d) level of theory. Absorption spectra of investigated PDI derivatives cover whole UV-Visible region which indicate that studied molecules could be used efficiently for photovoltaics. The R*(λmax – λmin) value of PDI derivatives is red shifted due to CN substitution while it resulted in slightly blue shift due to NO2 substitution. In addition, reorganization energy (λ) values found to be lowered by all substituents but more efficiently by SO2 and CN substituents. Molecular electrostatic potential surfaces and chemical reactivity indices have also been calculated to verify results. Furthermore, investigated acceptor molecules have been matched with suitable donors (based on benzo [2.1-b:3.4-b′] dithiophene derivatives D1–D5) to verify their practical efficiency. The calculated open circuit voltage (Voc) of investigated PDI derivatives is fairly high with donors D1 (0.95–1.34) and D2 (0.54–0.92). This study can be beneficial in future investigations of donor-acceptor materials for organic photovoltaic devices.