First theoretical engineering of robust C-C single bond-based acceptor materials for efficient organic photovoltaics

Organic photovoltaics with prolonged photo stability need further attention from researchers around the world. In this report, a new series of photostable acceptor molecules for possible applications in organic photovoltaics have been presented. In these molecules, a robust carbon-carbon single bond initiates a unique N-S covalent interaction that enhances the photo and thermal stability of the studied designed systems. In this regard, density functional theory (DFT) and time-dependent density functional theory (TD-DFT) have been employed at different appropriate levels. The position of frontier molecular orbitals (FMOs) reduces the band gap with maximum charge transportation. Further, the modeled systems have also shown light absorption in the near infra-red (IR) region with easy excitation of the exciton. High electron and hole mobilities towards the respective electrodes are also noted for the studied systems (SSFL-1 to SSFL-4). Finally, enhanced fill factor (FF%) along with high power conversion efficiency (PCE) of 21.36 % is noted in the designed systems.