Abstract
In the quest to improve the performance of organic solar cells (OSCs), the distinction of the critical factors limiting their power conversion efficiency (PCE) with a view to rationalizing the relationship between the structures of the active layers, their morphology, and the electronic processes taking place at their interface is required. In this review, we give an overview of the role of computational approaches based on density functional theory (DFT) in describing and predicting the structure of OSC active materials at molecular level and characterizing their various properties. We first discuss the key success of DFT calculations in establishing and understanding the relationship between the structure and the optoelectronics properties of some organic compounds. A second section deals with the power of DFT calculations in the molecular design of potential donor materials for photovoltaic applications which is beneficial for chemists to have an estimate of the photophysical properties of the target before carrying out a multistep synthesis.