Engineering of Asymmetric A1-D1-A2-D2-A1 type non-fullerene acceptors of 4T2CSi-4F Derivatives to Enhance Photovoltaic Properties: A DFT study

Abstract

Designing efficient, non-fused ring-based organic solar cells (OSCs) with high open circuit voltage is a significant challenge. The present research proposes seven novel moieties generated from an existing 4T2CSi-4F (R) asymmetric molecule to increase efficiency. The density functional theory (DFT) was used to examine several essential characteristics like optical, electronic, and efficiency-related properties of molecules. It is revealed that newly presented molecules have superior features that are required to manufacture efficient organic solar cells. They exhibit a lower band gap between 2.05 – 2.34 eV and have a planar shape. Six moieties exhibit lower excitation energy in the gas and chloroform phases, and five moieties have more excellent dipole moments than the R molecule. UA1 and UA2 show remarkable enhancement in the optoelectronic properties, exhibiting the greater λmax at 773 nm and a smaller excitation energy of 1.60 eV. All the newly presented molecules have lower ionization potential and reorganization energies of the electron. The open circuit voltage (Voc) of five newly designed molecules is greater, varying from 1.40 to 1.55 eV, than R (Voc=1.38 eV). Furthermore, the newly designed molecules, except UA1 and UA2, show more excellent fill factor (FF) than the R molecule. This significant increase in efficiency-associated metrics (FF and Voc) suggests that these molecules may be effectively implemented to manufacture an upgraded version of OSCs.