Physicochemical insights into the rational designing of new acceptor molecules by donor bridge modifications for efficient solar cells: In silico chemistry

In small-molecule organic solar cells (SM-OSCs), it remains a big challenge to obtain favorable bulk heterojunction morphology by acceptor material design. In this report, efforts are being made to design efficient acceptor molecules for the active layer of the organic solar cell. Donor bridge modifications have been made by using effective donor units, and thus, four new molecules (KSD1–KSD4) have been designed and examined theoretically. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) have been employed for the calculation of various geometric and structural parameters. Transition density matrix, open-circuit voltage, reorganizational energy of hole and electron, and photovoltaic characteristics of newly designed molecules have been examined through quantum chemical techniques. Additionally, the frontier molecular orbital analysis along with excitation and binding energies has been performed for these molecules. A narrow bandgap with a redshift in absorption spectrum is observed for KSD1–KSD4 molecules. Results of different analyses have recommended that the designed molecules are effective contributors for organic solar cell applications.