Modeling of an efficient donor-π-acceptor-π organic solar cell: a first principle study of a hole–electron process by DFT and TD-DFT study

New renewable energy sources, like solar cells, demonstrated to have environmental difficulties, pricing efficiency and other problems. In this study, the hole–electron theory has been applied by DFT and TD-DFT modeling to simulate an organic solar cell (OSC) with the special capabilities. This designed OSC applies a π-donor-π-acceptor system. It was demonstrated that Heme molecule could be chosen as an acceptor agent in this system. The modeled system has been modified by an efficient acceptor with four C₆₀ fullerenes. This modeled system is considerable as an important charge and electron transfer at visible wavelengths of approximately 574 nm. The investigations were conducted in the two ground and excited states. The results have given a comprehensive picture of how the discussed OSC acts. The electron-donating part of this OSC actually consists of two S-donors that are connected by pyrazino[2,1,6-de]quinolizine linker. The energies of the all LUMO orbitals from donor part, Heme molecule, C₆₀ and Heme + C₆₀ (acceptor part) are cascaded from top to bottom.