Simultaneously enhanced efficiency of eco-friendly structural characterization of the dithienocyclopentacarbazole donor based acceptors with narrow bandgap for high-performance organic solar cells

Abstract In the present age, researchers are trying to overcome the energy crisis and the global demand for energy by developing organic solar cells (OSCs) of higher efficacy. Herein, we have developed five new acceptor molecules with a dithienocyclopentacarbazole donor unit flanked with different electron-withdrawing end-capped acceptor units, named Z1 ((Z)-2-(2-ethylidene-5,6-difluoro-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile), Z2 ((Z)-1-(dicyanomethylene)-2-ethylidene-3-oxo-2,3-dihydro-1H-indene-5,6-dicarbonitrile), Z3 ((Z)-2-(5-ethylidene-4-oxo-4,5-dihydro-6H-cyclopenta[b]thiophen-6-ylidene)malononitrile), Z4 ((Z)-2-(5-ethylidene-3-fluoro-4-oxo-4,5-dihydro-6H-cyclopenta[b]thiophen-6-ylidene)malononitrile) and Z5 ((Z)-5-((Z)-5-ethylidene-4-oxo-4,5-dihydro-6H-cyclopenta[b]thiophen-6-ylidene)-3-methyl-2-thioxothiazolidin-4-one) to get greater effectiveness and good activity of OSCs, in order for non-renewable resources to be replaced with cost-effective, better-performing OSCs. B3LYP/6-31G(d,p) was used analytically to explore the maximum absorption wavelength ( λ max ), reorganization energy ( RE ), frontier molecular orbital, transition density matrix, open circuit voltage ( V oc ), density of state, binding energy ( E b ) and dipole moment of the newly developed molecules. Amongst all the newly designed ( Z1 – Z5 ) molecules, the Z2 molecule showed the lowest energy gap (2.04 eV) between highest occupied molecular orbital and lowest unoccupied molecular orbital, maximum λ max value in the applied phases i.e. gas (680.74 nm) and solvent (737.0 nm) along with the highest dipole moment values in gas (9.85 Debye) and solvent phase (11.0 Debye), lowest values of reorganization energy, and high charge mobilities. In addition, all the newly designed molecules were found to have the potential for better results in contrast to the molecule R (reference molecule).