Optoelectronic properties of naphthalene bis-benzimidazole based derivatives and their photovoltaic applications

• Four NDI based acceptor molecules have been designed through functionalization of reference. • Comparative analysis suggested better photo-physical properties of newly proposed structures. • The designed acceptor molecules have promising optoelectronic properties. In the current study, the four molecules ( F1-F4 ) have been designed to augment the efficiency of organic photovoltaic (OPV) devices by employing different acceptor moieties named as 2-methylenemalononitrile ( F1 ), 2-(2-methylene-3-oxo-2,3-dihydroinden-1-ylidene) malononitrile ( F2 ), 3-methyl-5-methylene-2-thioxothiazolodin-4-one ( F3 ) and methyl 2-cyanoacrylate ( F4 ). All the designed molecules shared same acceptor core named as naphthalene bis benzimidazole linked with acceptor groups at peripheral positions through thiophene. Comparative analysis has been conducted using selected hybrid functional WB97XD/6-31G (d, p) between designed molecules and reference molecule to interpret their optoelectronic properties such as Frontier molecular orbitals, Density of States, Reorganization energies, Transition density matrix analysis. Optical properties at TD-DFT predicted that F2 molecule has better UV-absorption as compared to reference molecule R . Reorganization energies, lower binding energies and higher open circuit voltage values have been predicted which showed that these designed molecules could be the best substitute for charge transporting materials. All these theoretical calculations showed that the designed acceptor molecules have outstanding optoelectronic properties in future utilization as compared with reference molecule.